$Id: CHANGES,v 1.177 2007/10/06 13:02:07 mikpe Exp $

			CHANGES

			=======

[High-level changes in reverse chronological order. Detailed

 driver changes are in linux/drivers/perfctr/RELEASE-NOTES.]

Version 2.7.21.1, 2007-10-06

- ppc64: recognise the PowerPC 970MP.

- Perfex: On ppc64, do not truncate the MMCR1 value to 32 bits.

  Bug fix from Philip Mucci.

Version 2.7.21, 2007-10-03

- Updated to support kernels 2.6.18 to 2.6.22. The system

  call numbers used in these kernels differs from those used

  in older kernels. The user-space library has been updated

  and will support both these newer kernels as well as the

  older kernels supported by perfctr-2.7.19/2.7.20/2.7.20.2.

- Corrected kernel driver Makefile to unbreak call-site

  backpatching in the x86 driver.

- Updated x86 driver to match the one in perfctr-2.6.28 in

  terms of fixes, CPU support, and kernel version support.

- Updated references to my email address and perfctrs' web URL

  to match current reality.

Version 2.7.20.2, 2006-08-27

- Changed library to adjust its system call numbers based

  on the running kernel's version. Provides compatibility

  with kernels using perfctr-2.7.19 or perfctr-2.7.20.

Version 2.7.20.1, 2006-08-25

- Added patch file for a SuSE 2.6.16.21-SLES10 kernel.

  Contributed by Eric Kjeldergaard @ IBM.

Version 2.7.20, 2006-08-20

- Updated to support kernels 2.6.16, 2.6.17, and 2.6.18-rc4.

- Migrated ppc64 from include/asm-ppc64/ to include/asm-powerpc/.

- Updated perfctr system call numbers on all platforms, due to

  other system call additions since kernel 2.6.14.

Version 2.7.19, 2005-11-08

- The self and signal examples have been updated for Power5/PPC970.

- The ppc64 driver has been updated to compile correctly in

  recent 2.6 kernels.

- The x86 kernel driver has been updated to work correctly

  on dual-core P4 processors. Previous versions would fail

  during CPU detection (on HT DC P4s) or would erroneously

  restrict access for one of the cores (non-HT DC P4s).

- The ppc32 driver will now compile in kernels that lack Open

  Firmware support, which is needed for some embedded systems.

Version 2.7.18, 2005-06-06

- Fixed a 32/64-bit bug in the vperfctr_read_ctrs() library

  function, which caused problems on ppc64 and unnecessary

  overheads on x86. The bug was introduced in perfctr-2.7.16.

  From David Gibson.

Version 2.7.17, 2005-05-26

- On all architectures the low-level drivers now indicate changes

  to the mmap:ed counter state via a standard seqlock mechanism.

  This cleans up the code, enables user-space fast sampling in

  some previously impossible cases (x86 w/o TSC), and eliminates

  a highly unlikely but not impossible failure case on x86 SMP.

- Fix counter wraparound issues in ppc64 driver. From David Gibson.

- Preliminary code in the x86/x86-64 low-level driver to detect

  multicore AMD K8 processors, and to prevent resource conflicts

  and an erratum related to northbridge events. On multicore K8s,

  northbridge events are only allowed when using the global-mode

  counters API.

Version 2.7.16, 2005-04-09

- In user-visible mmap()ed state, counter start values are now

  64-bit fields (values are still 32 bits however). Moved the

  virtual-to-physical counter mapping out of the user-visible

  mmap()ed state; the library now maintains that mapping.

- On ppc32/ppc64, the mmap()ed state now includes a software

  counter which the low-level driver increments at each sampling

  operation. Unfortunately the PPC timebase has too low frequency

  for it to be a reliable context-switch indicator for user-space.

- Makefile tweaks for cross-compilation and 'mrproper'.

- Removed references to the obsolete /dev/perfctr special file

  in INSTALL and perfctr.spec.

Version 2.7.15, 2005-03-31

- ppc64 updates from David Gibson for the user-space components

  and <asm-ppc64/perfctr.h>. User-space now compiles and appears

  to work on ppc64.

Version 2.7.14, 2005-03-29

- Slight change to the layout of the mmap()able counter state

  object. User-visible fields are now contiguous and have been

  moved to a sub-struct. Kernel-private fields in the state

  are no longer visible to user-space. Added a sysfs attribute

  containing the offset from the start of the mapping to the

  user-visible state.

- The number field in CPU register descriptors has been

  extended to 64 bits on all platforms. This is needed to

  prevent 32-bit binaries from breaking on 64-bit kernels.

Version 2.7.13, 2005-03-23

- x86: Fixed a problem with the finalising of backpatchable

  calls that caused it to miss some call sites when the

  kernel is compiled with gcc-4.0.

- ppc32: Fixed a bug where failure in a specific control

  validation check could leave the state semi-runnable.

  This was caused by a driver change in perfctr-2.7.11.

- The value field in CPU register descriptors has been

  extended to 64 bits on all platforms. This is needed

  now for ppc64 and ppc32, and may later be needed on x86.

- Added David Gibson's ppc64 code for perfctr-2.7.10.

  The driver code has been updated to the current APIs.

  The user-space code has not been updated, so currently

  it does not compile on ppc64. This will be fixed soon.

Version 2.7.12, 2005-03-18

- Header cleanups: Moved declarations for things now unused

  in the kernel from the kernel headers to the user-space

  library. Changed kernel declarations of kernel/user-space

  API structures to use explicitly-sized integer types.

- Removed unused /sys/class/perfctr/cpu_type file.

Version 2.7.11.1, 2005-03-14

- Corrected the patch for kernel 2.6.11. A 'diff' mistake

  caused the one in perfctr-2.7.11 to be incomplete.

Version 2.7.11, 2005-03-14

- The kernel/user-space APIs have been converted to transmit

  control data in differently-shaped "packets" for different

  types of data. Data corresponding to CPU register images is

  transmitted as variable-length <regnr,regvalue> arrays.

  Potentially variable-sized arrays are no longer embedded in

  other API structures, but are transmitted separately. These

  changes should eliminate "binary struct" versioning problems.

- Since the library/application API had to change, the API

  structures were made compatible with perfctr-2.6.x again.

  (Reverted misguided API change in perfctr-2.7.8.)

  Added code to translate control data between the application

  format and the syscall formats.

- The system calls have been renumbered again on all platforms.

Version 2.7.10, 2005-02-20

- The kernel/user-space API for uploading control data and

  performing state changes has been updated. Writing control

  data no longer implies restarting a context. There is a new

  unified state changing operation for suspending, resuming,

  unlinking, and clearing contexts. This is preparation for

  a follow-up API change which will make control data uploads

  more generic and less sensitive to 'struct' layouts.

  The user-space library hides these changes from applications.

- The system calls have been renumbered on all supported platforms,

  due to the merging of several state-changing system calls.

Version 2.7.9, 2005-01-16

- The kernel components now publish global information via sysfs,

  in /sys/class/perfctr/. Removed the perfctr_info() system call.

  The library has been updated accordingly. (One omission: parsing

  of files containing "cpumasks" is not yet implemented.)

- The system calls have been renumbered on all supported platforms,

  due to the removal of sys_perfctr_info() and to other system

  calls being added recently.

- Fixes forward-ported from perfctr-2.6.12:

  * On x86/x86-64, perfctr_event_codes.h now includes P4 events.

  * On x86-64 libraries will now be installed in PREFIX/lib64/,

    as per current standards, unless overridden by LIBDIR.

  * Perfex had a bug in which it interpreted all numbers as hex,

    even those without "0x" prefixes. Perfex now emits warnings

    for ambiguous numbers. To silence the warnings, (a) prefix

    hex numbers with "0x" (preferred), or (b) use the "-d" option

    to enable decimal numbers, which requires "0x" prefixes on

    hex numbers, or (c) use the "-x" option to force all numbers

    to be interpreted as hex (deprecated). The "-d" option should

    be the default, but unfortunately that would break user-level

    scripts that assumed that "0x"-less numbers are still hex.

  * Changes in examples/signal/ to handle glibc-2.3.3 on PPC32.

Version 2.7.8, 2004-11-24

- Changed the sys_vperfctr_control() API to handle future

  processors with more counters, and to allow for reduced

  syscall argument copying when only a small number of counters

  are being used. Converted the per-counter control fields

  from a struct-of-arrays to an array-of-struct layout.

Version 2.7.7, 2004-11-13

- Workarounds for a hardware quirk on x86 and x86-64, where

  interrupts can be delivered some time after the counters have

  been stopped. Due to scheduling, an interrupt could be taken

  in the context of an unrelated process, which would prematurely

  terminate interrupt reporting for the original process.

- Fixed a bug in the x86 and x86-64 kernels where the context-switch

  path suspended the previous process' performance counters too late.

  This could allow an overflow interrupt to be taken in the context

  of an unrelated process, with effects similar to the hardware quirk

  described above.

- PPC32 updates: Enable overflow interrupts on all G4 processors

  starting with the 7410 Rev 1.3, and all IBM G3 processors starting

  with the 750FX DD2.3. Add support for MPC7447A and MPC7448.

- Kernel/user-space API change for sys_vperfctr_read().

- System call numbers changed.

Version 2.7.6, 2004-10-19

- Added preliminary overflow interrupt support for PPC32.

  There are currently several limitations of this feature:

  * Only enabled on MPC7455 processors. Will later be enabled

    on all G4 processors except 7400 and early 7410.

  * Either none or all of the "PMCj" group counters (i.e.,

    all but PMC1) must be marked as interrupt-mode counters.

    This is because PPC32 doesn't provide per-counter interrupt

    enable/disable control. User-space should ignore overflow

    signals from counters it isn't interested in.

- Corrected the PPC32 driver's handling of MMCR0 changes due

  to use of the FCECE or TRIGGER control flags.

- Fixed a synchronisation error in the interface between

  the per-process counters driver and the low-level drivers.

  The error triggered warnings in DEBUG_SPINLOCK_SLEEP-

  enabled kernels.

Version 2.7.5.1, 2004-09-19

- i386 and x86_64 system call numbers have changed: updated

  library and 2.6-vanilla kernel patch accordingly.

- Fixed a problem causing an incomplete "wrapper" file to be

  installed as /usr/include/asm/perfctr.h on x86_64 systems.

- Eliminated a potential kernel crash on P4 model 3 Prescott

  processors, due to the driver initialising two control

  registers that have been removed from P4M3. The P4M3 Nocona

  does not appear to have been affected by this error.

- Fixed install procedure to not fail to install the shared

  library's symbolic links when updating an older installation.

Version 2.7.5, 2004-08-18

- Some x86 driver cleanups.

- Minor fixes to the driver init testing code on x86-64.

- Fixed update-kernel script to use 'head' in a POSIX

  compliant way.

- Updated user-space library and examples to handle P4 Model 3

  in 64-bit mode.

- Fixed an unforseen kernel synchronisation error with the

  newly added perfctr inheritance code. The error triggered

  warnings in CONFIG_DEBUG_SPINLOCK_SLEEP-enabled kernels.

- Fixed another kernel locking rule violation in the new

  perfctr inheritance code.

- Fixed an x86 driver initialisation bug which could cause

  it to disable the NMI watchdog prematurely.

Version 2.7.4.1, 2004-07-18

- Add patches directory with patches for kernels 2.6.8-rc1-mm1

  and 2.6.8-rc2. A CVS mistake caused these files to not be

  included in perfctr-2.7.4.

Version 2.7.4, 2004-07-17

- Reimplemented inheritance of per-process perfctrs. Their

  settings are now inherited across fork(). At wait(), if

  parent and child still use the same control, the child's

  final counts (its and its childrens') are merged into the

  parent's "children counts". The perfex application will now

  show the sum of the self and children counts for each counter.

- Bug fix for PowerPC 7400/7410: allow specifying MMCR2[THRESHMULT].

- Added documentation in linux/Documentation/perfctr/.

- Reduce stack usage in sys_vperfctr_control() and sys_vperfctr_read().

- PPC32 now supports generic chips in timebase-only mode. Useful for

  high-resolution time measurements on generic chips.

- Add support for Model 13 Pentium-M (Dothan).

- Many code cleanups.

Version 2.7.3, 2004-05-31

- Replaced the single system call by six system calls: one

  for getting CPU information, and 5 for per-process perfctrs.

- Removed marshalling of system call parameters. Conventional

  copying is now done.

- Temporarily removed global-mode perfctrs, while the API

  to the per-process perfctrs is being redesigned.

- Changed x86-64 to use the x86 code. Simplifies maintenance,

  and, in theory, adds support for IA32e/EM64T.

- Moved detailed CPU type detection on x86 from the driver

  to the library. This is both a cleanup and a bug fix.

- Some changes to prepare the ppc32 data structures for

  potential G5/970 support, in both 32 and 64-bit kernels.

- PowerPC 750GX support added.

- Moved ppc32 #define:s to <asm-ppc/reg.h>.

- Lots of code cleanups. Converted NR_CPUS arrays to per_cpu().

  Changed spacing in if/while/switch to be "normal".

Version 2.7.2, 2004-05-14

- Changes for submission to 2.6.6-mm kernel. Replaced

  ioctl() interface by new syscall (by request, not choice).

  Eliminated module support and backwards compatibility.

  Many other cleanups.

Version 2.7.1, 2004-05-10

- Updated the x86 and x86-64 drivers for the final version

  of the local APIC ownership API included in kernel 2.6.6.

  Perfctr and Oprofile can now coexist safely.

Version 2.7.0, 2004-05-04

- Added a minimal performance counter resource management API

  to the kernel patch. This allows different drivers to claim

  the hardware as they need it, without risk of conflicts.

  Tested with the NMI watchdog, oprofile, and perfctr all

  loaded (but obviously not active) at the same time.

  Available for the 2.6.6-rc3 kernel.

- Significant rewrites in the x86 and x86_64 low-level drivers

  for the new API. Instead of reserving the hardware as long as

  the driver is loaded, it is reserved and released dynamically

  based on whether the high-level driver needs it or not.

Version 2.6.7, 2004-05-04

- Merged several x86_64-specific driver files with their x86

  counterparts, reducing the amount of duplicated code.

- Added textual descriptions to the library's P6 event sets.

  From Bryan O'Sullivan.

- Changed examples/signal/signal to count retired instructions

  instead of retired micro-operations on AMD K7. Needed to avoid

  a loop with the same instruction overflowing indefinitely.

- Updated kernel support: 2.6.6-rc3, 2.4.27-pre1, 2.4.22-1.2188.nptl

  (FC1), 2.4.21-9.0.1 (RHEL3), 2.4.20-31.9 (RH9).

Version 2.6.6, 2004-02-21

- Pentium-M has an undocumented local APIC quirk which can stop

  perfctr interrupt delivery. Added workaround to prevent this.

- Fixed a bug in x86-64's perfctr interrupt entry code in 2.4 kernels.

  Luckily, the bug turned out to be harmless (a bogus "rip" value was

  retrieved, but never used by the higher-level interrupt handler).

- Added support for Pentium 4 Model 3 processors, which have slight

  event set changes from earlier models.

- Updated kernel support: 2.6.3, 2.4.25, 2.4.22-1.2174.nptl (FC1),

  2.4.20-30.9 (RH9), and 2.4.21-193 (SuSE). Removed support for some

  obsolete FC1 and RH update kernels.

Version 2.6.5, 2004-01-26

- Relaxed and corrected control checks on Pentium 4:

  * Allow ESCR.CPL_T1 to be non-zero when using global-mode

    counters on HT processors.

  * Don't require ESCR.CPL_T0 to be non-zero. CPL_T0==0b00

    is safe and potentially useful (global counters on HT).

  * Require CCCR.ACTIVE_THREAD==0b11 on non-HT processors, as

    documented in the IA32 Volume 3 manual. Old non-HT P4s

    seem to work Ok for all four values, but this is neither

    guaranteed nor useful.

- Per-process counters driver updated for filp->f_mapping

  change in 2.6.2-rc kernels.

- Support 2.4.21-9.EL (RHEL3) and 2.4.22-1.2149.nptl (FC1) kernels.

- Library updates for PowerPC:

  * Added cpu_type constants for struct perfctr_info.

  * Decode PVR and define perfctr_info.cpu_type accordingly.

  * Added event set descriptions for 604/604e/750.

Version 2.6.4, 2004-01-12

- Added support for PowerPC 604/7xx/74xx processors.

  * Overflow interrupts are not yet supported due to a hardware

    erratum affecting many 7xx and early 74xx processors.

  * The user-space components support PowerPC, but CPU detection

    and event set descriptions are not yet implemented.

  * Supported in 2.6.1 and 2.4.23 and newer 2.4 kernels.

- Updated kernel support: 2.6.1, 2.4.25-pre4, 2.4.22-1.2140.nptl

  (FC1 update), 2.4.21-4.0.2.EL (RHEL update), and 2.4.20-28.x

  (RH 7.x/8.0/9 update).

Version 2.6.3-pl1, 2004-01-01

- Updated kernel support: 2.6.1-rc1, 2.4.24-pre3,

  2.4.22-1.2135.nptl (FC1 update), 2.4.21-6.EL (RHEL Taroon

  beta update), and 2.4.20-27.x (RH 7.x/8.0/9 update).

- Moved the x86 performance counter interrupt handler code

  from the driver source to the kernel, via the patch kit.

  Needed to cope with changes in RedHat's 2.4.21-6.EL kernel.

  This change only affects 2.4.21 and later 2.4 kernels.

Version 2.6.3, 2003-12-21

- Fixed a bug where a read of the global-mode counters could

  fail with EOVERFLOW due to an incorrect structure descriptor.

  The bug only existed in perfctr-2.6.2.

  (Thanks to Pavel Machek for reporting this problem.)

- AMD64 IA32 emulation code cleaned up for kernel 2.4.23.

- Updated kernel support: 2.6.0, 2.4.24-pre1, 2.4.23,

  2.4.22-1.2129.nptl (FC1 update), 2.4.21-1.1931.2.393.ent

  (RHEL Taroon beta), and 2.4.20-24 (RH 7.x/8/9 update).

- User-space package rpm spec file fixes:

  * Don't remove /dev/perfctr on package uninstall.

  * Don't add alias to /etc/modules.conf if it's already there.

Version 2.6.2, 2003-11-23

- libperfctr.so is now installed with proper versioning.

- ABI control and info structures padded to accommodate some

  extensions without breaking application/library binary

  compatibility. ABI version incremented to '5'.

- Driver checks that only P4 models <= 2 use IQ_ESCR0/1.

- Added support for Fedora Core 1's 2.4.22-1.2115.nptl kernel.

- Driver compile fix for AMD64 in SMP 2.6 kernels.

Version 2.6.1, 2003-10-05

- Opening a process' virtual perfctrs is now done via

  /dev/perfctr instead of /proc/<pid>/perfctr. This is needed

  due to the changed semantics for /proc/self and /proc/<pid>/

  in kernel 2.6.0-test6. User-space is not affected since the

  perfctr-2.6 API and user-space library was prepared for

  this access method change.

  User-space code monitoring other processes should use

  gettid() to identify tasks in 2.6 kernels, since getpid()

  does the wrong thing for process threads.

- Driver cleanups from obsoleting 2.4.15 and older kernels.

- Made examples/global/global.c more robust.

- Simplified usage with 2.6 kernels: it's no longer necessary

  to add an 'alias' declaration in /etc/modprobe.conf.

- Added support for AMD K8 Revision C processors.

Version 2.6.0, 2003-09-08

- The driver now kills a process' performance counters if the

  process migrates to a forbidden CPU. This ensures that unsafe

  changes to a process' CPU affinity mask don't break the driver,

  the hardware state, or other processes. (This is an issue on

  hyper-threaded P4s only.)

- A bug fix in perfctr-2.6.0-pre3 broke compiling the driver

  non-modular in modular 2.4 kernels. Corrected that problem.

Version 2.6.0-pre5, 2003-08-31

- Disabled driver debug code which could printk() in the kernel's

  context-switch path, as that is disallowed.

- 2.4.16 is now the oldest supported kernel.

- Compilation fixes for driver's ia32 emulation code on x86-64.

Version 2.6.0-pre4, 2003-08-19

- Kernel/user-space API switched to a new "sparse marshalling"

  mechanism, which supports x86 application code on x86-64,

  and API struct extensions w/o breaking binary compatibility.

- Prepared the library for the future non-/proc/pid/perfctr API.

- Fixed a bug in the per-process perfctr creation code. The

  remote-control interface was racy in preemptible kernels.

- Fixed a bug in the process exit code for preemptible kernels.

- Changes to handle 2.6 kernels with the cpumask_t patch (-mm, -osdl):

  * Driver converted to use cpumask_t API, with compatibility wrapper

    for cpumask_t-free kernels.

  * API change: removed the cpus and cpus_forbidden sets from the

    perfctr_info struct, added new data type and commands for retrieving

    these sets. (cpumask_t values cannot be exported as-is since their

    sizes depend on kernel configuration, and the type definition uses

    'long' which breaks 32/64-bit binary compatibility.)

  * Updated library and example programs for the API change.

- Fixed a dependency bug in the library Makefile.

- Added support for VIA C3 Antaur/Nehemiah processors.

Version 2.6.0-pre3, 2003-08-03

- Replaced 'long' by 'int' in the API structures to eliminate

  unnecessary ABI incompatibilities between x86 and x86-64.

- Simplified global-mode perfctrs API: the write-control and

  read-state commands now operate on a single CPU instead of on

  a set of CPUs. Added a new start command to start the counters.

- Added thin library wrappers for per-process perfctr kernel calls.

  Cleaned up examples/perfex and the library itself.

- Removed the requirement that CCCR.ACTIVE_THREAD == 3 on P4.

- Extended cascading should now work on Pentium 4 Model 2 processors.

- Fixed a bug where the perfctr module's refcount could be zero with

  code still running in the module. This could race with rmmod in

  preemptive kernels, and in theory also in SMP kernels.

Version 2.6.0-pre2, 2003-07-13

- Per-process perfctrs API fixes: control data is retrieved using

  new READ_CONTROL operation, mmap()ed state no longer exposes the

  control data, the SAMPLE operation is renamed to READ_SUM and

  now updates a given user-space buffer, non-write operations are

  permitted on dead perfctrs.

  Retrieving control explicitly makes the user-visible mmap()ed

  state binary compatible between x86 and x86-64. The other changes

  simplify the user-space library and allow perfex to replace raw

  mmap() accesses with higher-level operations.

- Driver cleanups, including eliminating many #ifdefs and

  removing some unnecessary P4-specific driver procedures.

- Fixes for macro redefinition warnings in the 2.4.22-pre3 kernel.

- Perfctr library RPM spec file updates from Bryan O'Sullivan.

Version 2.6.0-pre1, 2003-07-02

- Rearranged the data structure holding the counter state to

  reduce the number of caches lines needed to be touched at key

  operations. The new representation is also binary compatible

  between x86 and x86-64, which matters since user-space mmaps() it.

- Added RPM spec file for the library. (From Bryan O'Sullivan).

- Patch kit updated for kernels 2.4.22-pre2 and 2.5.73.

Version 2.5.5, 2003-06-15

- Updates for driver model changes in kernel 2.5.71.

- Minor updates to the library's event descriptions for Pentium 4.

- Now supports SuSE's 2.4.19.SuSE-206 kernel for SLES 8 users.

  Autodetection of SuSE kernel versions is not yet implemented:

  pass "--patch=2.4.19.SuSE-206" to perfctr's update-kernel script

  to ensure that the correct patch is applied.

- Patch kit updates for 2.4.21 final and 2.4.20-18 RH kernels.

Version 2.5.4, 2003-06-01

- Corrected the driver's handling of OVF_PMI+FORCE_OVF counters

  on Pentium 4. This configuration didn't work at all, and

  lead to various BUG messages from the driver.

  These restrictions apply to OVF_PMI+FORCE_OVF counters:

  * The ireset value must be -1.

  * Once the counter has interrupted once, it will continue

    to interrupt when the faulting instruction is restarted,

    causing it to never complete. This problem also occurs

    for non-FORCE_OVF interrupt-mode counters if the ireset

    value is of too small magnitude, like -1.

    This appears to be a P4 hardware quirk. Don't restart

    FORCE_OVF interrupt-mode counters, and don't use ireset

    values too small to allow instructions to complete.

- Updated library's K8 event descriptions to match current

  documentation. Corrected several omissions and errors.

- Patch kit updated for kernels 2.5.70 and 2.4.21-rc6.

Version 2.5.3.1, 2003-05-21

- Patch kit updated for recent RedHat 6.2/7.x/8.0/9 update kernels

  (2.2.24-{6.2.3,7.0.3} and 2.4.20-13.{7,8,9}).

- Fixed a driver compile warning which occurred when the driver

  is built as a module in 2.4 SMP kernels using module versions.

- x86-64 now uses 'long long' for 64-bit sums, like x86. This

  reduces x86 and x86-64 user-space source code incompatibility.

Version 2.5.3, 2003-05-16

- Added support for the Pentium M processor. It is mostly like

  a Pentium III with some more events, except that six old

  Pentium III / Pentium Pro events have been redefined.

- Added support for K8 in 64-bit mode (the x86_64 kernel arch).

  Updated driver, user-space library, and example programs.

  The shared library libperfctr.so is now compiled with -fPIC.

- K8 bug fix in examples/signal/signal.c: a missing INT flag

  caused the driver to reject the control setup.

- P4 event descriptions updated from recent documentation changes.

Version 2.5.2, 2003-04-13

- Updated power management code for the local APIC and NMI

  watchdog driver model changes in kernel 2.5.67.

- Timer-based sampling of per-process performance counters is

  now always enabled: previously it was only done on SMP.

  Needed to avoid counter inaccuracies on high core-clock CPUs.

- Fixes to user-space library implementation of remote-control

  virtual performance counters: open() failed due to a missing

  return; avoid potential buffer overflow error; fix the "read

  counters" procedure for the case where the remote process is

  sampling the time-stamp counter but no performance counters.

- Added support for RedHat 9's 2.4.20-8 and 2.4.20-9 kernels.

Version 2.5.1, 2003-03-23

- Fixed initialisation on hyper-threading capable P4s in

  SMP kernels older than 2.4.15 to not signal an error if

  hyper-threading is disabled: in this case the absence of

  working set_cpus_allowed() support is not a problem.

- Fixed two compilation errors in the set_cpus_allowed()

  emulation affecting old 2.4 kernels configured for SMP.

- INSTALL file updates.

Version 2.5.0, 2003-03-10

- Added a simple user-space library API for accessing other

  processes' virtual performance counters. This uses a new

  type and a new set of operations since remote access has

  different requirements than accessing one's own counters.

  Following Mike Marty's suggestion, I left out the process

  control calls needed around these operations (ptrace() and

  wait()), so applications must handle that themselves.

- Added 'make install' support for the user-space components.

- Driver API cleanups. The 'eventsel_aux[]' array in 'struct

  perfctr_cpu_control' has been renamed as 'escr[]' and has been

  moved into the 'p4' sub-structure. (The change highlights the

  fact that this field was and is P4-only.) The 'version[]' string

  in 'struct perfctr_info' has been renamed to 'driver_version[]',

  since perfctr_info now also contains an 'abi_version' field.

  Some changes in the driver ABI: while not strictly necessary,

  they clean things up and make room for future changes. The ABI

  changed anyway from perfctr-2.4, so this shouldn't be a problem.

- Added a perfctr_cpu_control_print() procedure to the library,

  and updated the example programs to use it.

- Updated the perfex example program's help text to describe the

  syntax and meaning of event specifiers.

- Patch kit updates for 2.2.24/2.4.18-26(RedHat)/2.5.64 kernels.

Version 2.5.0-pre2, 2003-03-03

- Added a way for user-space to query the driver's ABI version,

  and updated the library to check it.

- Fixed <linux/perfctr.h> to not include <asm/perfctr.h> when

  perfctr hasn't been configured. This allows the patched kernel

  source to compile cleanly also in archs not supported by perfctr.

- Major patch kit overhaul. Updated configuration help texts.

  Removed unnecessary features and patches. Some cleanups. Added

  aliasing support to the 'update-kernel' script, which allows a

  patch to serve several kernels (when applicable).

- The perfctr configuration option was poorly placed. It is now

  at the end of the "Processor type and features" menu.

- Removed "notsc" kernel option support from the 2.2 kernel patches.

  To use the driver with an IDT WinChip (Centaur C6/2/3) CPU now

  requires a newer kernel with native "notsc" support.

- Driver fixes for changes in the 2.4.21-pre5 and 2.5.63 kernels.

Version 2.5.0-pre1, 2003-02-19

- Fixed the driver's API to support global-mode perfctrs on 2.5

  SMP kernels and asymmetric hyper-threaded P4 multiprocessors.

  Updated examples/global/global.c for the new API.

- Minor library cleanups. Updated example programs accordingly.

- API cleanup: Removed obsolete STOP command from the driver

  for virtual perfctrs. The library now uses CONTROL instead.

- Proper detection and support for AMD K8 processors. They are

  similar to the K7s, but the event sets are not identical.

- The library's event set descriptions have been redesigned and

  expanded to include unit mask descriptions and descriptions of

  Intel P4 and AMD K8 events. The etc/perfctr-events.tab text file

  has been removed since event_codes.h now is generated from the

  library's data structures.

Version 2.4.5, 2003-02-09

- Corrected the unit mask definition for the K7 SYSTEM_REQUEST_TYPE

  event in etc/perfctr-events.tab: WC is 0x02 not 0x04.

- Fixed two compile warnings which could be triggered in 2.5 kernels.

- Patch kit updates for 2.4.21-pre4/2.4.18-24(RedHat)/2.5.59-osdl2 kernels.

Version 2.4.4, 2003-01-18

- Fixed a context-switch bug where an interrupt-mode counter could

  increment unexpectedly, and also miss the overflow interrupt.

- Fixed some ugly log messages the new HT P4 support code added

  in perfctr-2.4.3 could generate at driver initialisation time.

- Added preliminary support for AMD K8 processors with the

  regular 32-bit x86 kernel. The K8 performance counters appear

  to be identical or very similar to the K7 performance counters.

Version 2.4.3, 2002-12-11

- Support for hyper-threaded Pentium 4s added. In a HT P4, the

  two logical processors share the performance counter state.

  HT P4s are therefore _asymmetric_ multi-processors, and the

  driver enforces CPU affinity masks on users of per-process

  performance counters to avoid resource conflicts. (Users are

  restricted to logical processor #0 in each physical CPU.)

  Limitations:

  * The kernel mechanism for updating a process' CPU affinity

    mask uses no or very weak locking, which makes certain race

    conditions possible that can break the driver's CPU affinity

    mask restrictions. For now, users should NOT use the

    sched_setaffinity() system call on processes using per-process

    performance counters.

  * Global-mode performance counters don't work on HT P4s due to

    limitations in the API. This will be fixed in perfctr-2.5.

  * 2.2 kernels don't have CPU affinity masks, and therefore can't

    support HT P4s.

Version 2.4.2, 2002-11-25

- Fixed a driver bug where it could fail to prevent simultaneous

  use of global-mode and per-process performance counters.

- Made the driver safe for preemptible 2.5 kernels.

- New patches for RedHat update kernels 2.2.22-6.2.2, 2.2.22-7.0.2,

  2.4.18-18.7.x, and 2.4.18-18.8.0.

Version 2.4.1, 2002-10-12

- Support RedHat 8.0's 2.4.18-14 kernel. Building perfctr as

  a module caused a namespace clash in this kernel. The fix

  required a change to the driver's kernel-resident glue code.

Version 2.4.0, 2002-09-26

- Fixed an overly strict access control check which prevented

  opening another process' /proc/<pid>/perfctr when the driver

  was built as a module.

- Updates for kernels 2.2.22, 2.4.18-10-redhat, 2.4.20-pre8, 2.5.36.

Version 2.4.0-pre2, 2002-08-27

- vperfctr_control() now allows the user to specify that some PMC

  sums are not to be cleared when updating the control.

  There is a new bitmap field `preserve' in struct vperfctr_control:

  if bit i is set then PMC(i)'s sum is not cleared.

  `preserve' is a simple `unsigned long' for now, since this type

  fits all currently known CPU types.

  This change breaks binary compatibility, but user-space code which

  clears the entire control record before filling in relevant fields

  will continue to work as before after a recompile.

  This feature removes a limitation which some people felt was a

  problem for some usage scenarios.

Version 2.4.0-pre1, 2002-08-12

- The kernel driver has an initial implementation of a new

  remote-control API for virtual per-process perfctrs.

  A monitor process may access a target process' perfctrs via

  open(), mmap(), and ioctl() on the target's /proc/pid/perfctr.

  For open() and ioctl(), the monitor must hold the target under

  ptrace ATTACH control. The user-space library and examples have

  not been updated for the new API.

Version 2.3.12, 2002-08-12

- Updated patch kit for the 2.4.19 final kernel.

- Spelling fix in INSTALL.

- Minor driver code size reduction on uniprocessor kernels.

Version 2.3.11, 2002-07-21

- Interrupt-mode performance counters now have accumulated sums.

  The library procedures vperfctr_read_pmc() and vperfctr_read_ctrs()

  can now retrieve the sums of interrupt-mode counters.

- Corrected the name of K7 event 0x42 to DATA_CACHE_REFILLS_FROM_L2.

Version 2.3.10, 2002-07-19

- Added a script, `update-kernel', to simplify the process of

  patching the kernel source code. See INSTALL for details.

- The counter and control registers are now cleared when the

  driver is idle. This should allow the counter hardware to

  power down when not used, especially on P4.

- Some Pentium MMX and Pentium Pro processors have an erratum

  which causes System Management Mode to shut down if user-space

  has been granted access to the RDPMC instruction. The driver

  now avoids granting RDPMC access on the affected processors.

  The user-space library makes this change transparent.

- New CPU type code for Model 2 Pentium 4s, due to a few but

  significant changes between Model 0 and 1 and Model 2 CPUs.  

- The driver now supports Replay Tagging on the Pentium 4.

  The perfex program has been updated to allow users to specify

  values to store in PEBS_ENABLE and PEBS_MATRIX_VERT.

  For example, the following command could be use to count the

  number of L1 cache read misses on a Pentium 4:

  perfex -e 0x0003B000/0x12000204@0x8000000C --p4pe=0x01000001 --p4pmv=0x1 some_program

  Explanation: IQ_CCCR0 is bound to CRU_ESCR2, CRU_ESCR2 is set up

  for replay_event with non-bogus uops and CPL>0, and PEBS_ENABLE

  and PEBS_MATRIX_VERT are set up for the 1stL_cache_load_miss_retired

  metric. Note that bit 25 is NOT set in PEBS_ENABLE.

Version 2.3.9, 2002-06-27

- Pentium 4 bug fix: An error in older revisions of Intel's IA32

  Volume 3 manual caused the driver to program the wrong control

  register in a few cases, affecting uses of the uop_type event.

  Revision -007 of Intel document #245472 corrects the error,

  and the driver has been updated accordingly.

Version 2.3.8.1, 2002-06-27

- Regenerated the patch file for RedHat's 2.4.18-5 kernel. The

  patch file in 2.3.8 only contained an error message from 'diff'.

Version 2.3.8, 2002-06-26

- Added counter overflow interrupt support for Intel P4.

- New kernel support: standard kernels 2.2.21 and 2.4.19-rc1,

  and RedHat kernels 2.2.19-7.0.16, 2.4.9-34, and 2.4.18-5.

- API changes: Removed unused and obsolete fields from the vperfctr

  state and control objects. Added fields to perfctr_cpu_control

  to enable future support for P4 replay tagging events.

  Incremented the vperfctr mmap() binary layout magic number.

- Changed the "make" rule in INSTALL to build "vmlinux" before

  "modules". This change is needed for RedHat kernels.

- Added build of a shared (.so) version of the user-space library.

- When changing a process' vperfctr control data, the TSC sum

  is now preserved if the next control state includes the TSC.

  It used to be preserved only if both the previous and next states

  included the TSC. The difference matters when a running TSC is

  stopped and then restarted by a STOP;CONTROL command sequence.

- Driver cleanups. Merged P6 and K7 driver procedures.

Version 2.3.7, 2002-04-14

- Added Pentium 4 support to examples/perfex/. The full

  syntax of an event specifier is now "evntsel/aux@pmc".

  All three components are 32-bit processor-specific numbers,

  written in decimal or hexadecimal notation.

  "evntsel" is the primary processor-specific event selection

  code to use for this event. This field is mandatory.

  "/aux" is used when additional event selection data is

  needed. For the Pentium 4, "evntsel" is put in the counter's

  CCCR register, and "aux" is put in the associated ESCR

  register. No other processor currently needs this field.

  "@pmc" describes which CPU counter number to assign this

  event to. When omitted, the events are assigned in the

  order listed, starting from 0. Either all or none of the

  event specifiers should use the "@pmc" notation.

  Explicit counter assignment via "@pmc" is required on

  Pentium 4 and VIA C3 processors.

  As an example, the following command could be used to count

  the number of retired instructions on a Pentium 4:

  perfex -e 0x00039000/0x04000204@0x8000000C some_program

  Explanation: Program IQ_CCCR0 with required flags, ESCR select 4

  (== CRU_ESCR0), and Enable. Program CRU_ESCR0 with event 2

  (instr_retired), NBOGUSNTAG, CPL>0. Map this event to IQ_COUNTER0

  (0xC) with fast RDPMC enabled.

- The driver now permits cascading counters on the Pentium 4.

- Preliminary driver infrastructure to support ptrace(ATTACH)

  for a future remote-control interface to per-process counters.

- Driver and patch kit updated for the APIC interrupt entries

  changes in kernel 2.5.8-pre3.

Version 2.3.6, 2002-03-21

- Fixed a problem with caused "BUG! resuming non-suspended perfctr"

  warnings when running PAPI's test cases with a DEBUG-compiled

  perfctr driver. There was no actual error, only a mismatch between

  the debug code and the code for changing event selection data.

- Fixed a time-stamp counter accounting error when user-space

  resumed interrupt-mode perfctrs with the VPERFCTR_IRESUME ioctl.

Version 2.3.5, 2002-03-17

- Multiprocessor AMD K7 machines should work now. A bug in current

  2.2/2.4/2.5 kernels prevented correct CPU identification on these

  machines, causing crashes. The driver now works around this bug.

- Added support for the VIA C3 Ezra-T processor.

- Added some support for interrupt-mode counters to the library.

  Cleaned up examples/signal/.

- Added links in OTHER to John Reiser's tsprof and Troy Baer's

  lperfex tools.

Version 2.3.4, 2002-01-23

- More detailed installation instructions in INSTALL.

- Experimental support for at-retirement counting on Pentium 4.

  Updated examples/global/ to count FLOPS on Pentium 4.

- Fixed uses of __FUNCTION__ to comply with changes in GCC 3.0.3.

Version 2.3.3, 2001-12-31

- Added support for the 2.4.16 and 2.4.17 kernels.

- SMP bug fixed: if a process using interrupt-mode counters migrates

  from CPU1 to CPU2 and then back to CPU1, then it could incorrectly

  resume the stale state cached in CPU1.

- P6 bug fixed: when a process resumed, it could inadvertently activate

  a suspended interrupt-mode counter belonging to the previous process

  using the performance counters.

- Pentium 4 bug fixed: could fail to update the control registers on a

  context switch.

- Removed the "pmc_map[] must be the identity function" restriction

  from P6 and K7.

- Updated examples/global/global.c: added Pentium 4 support

  (preliminary, counting MIPS not FLOPS), corrected VIA C3 handling,

  and corrected 32-bit integer overflow problems affecting fast CPUs.

- Removed perfctr_evntsel_num_insns() from the library: the interface

  could not support the Pentium 4. examples/self/self.c now does the

  setup all by itself, with Pentium 4 support.

Version 2.3.2, 2001-11-19

- Corrected an error in the driver's mapping from counter number

  to control registers on the Pentium 4. Counter 17 didn't work,

  and attempts to use it could have disturbed other counters as well.

- Fixed a minor omission in the Pentium 4 initialisation code.

Version 2.3.1, 2001-11-06

- New patches for kernels 2.2.20, 2.4.9-13 (RedHat 7.2 update),

  2.4.13-ac5, and 2.4.14. Minor cleanup in the P4 driver code.

Version 2.3, 2001-10-24

- Added support for multiple interrupt-mode virtual perfctrs

  with automatic restart. Updated the signal delivery interface

  to pass a bitmask describing which counters overflowed; the

  siginfo si_code is now fixed as SI_PMC_OVF (fault-class).

- Added EXPORT_NO_SYMBOLS to init.c, for compatibility with

  announced changes in modutils 2.5.

- Patch set updated for recent kernels.

Version 2.2, 2001-10-09

- Added preliminary Pentium 4 support to the driver, but only for

  the simple basic features. The example applications have not

  been updated, since I don't yet have a Pentium 4 for testing.

Version 2.1.4, 2001-09-30

- Added -l/-L (--list/--long-list) options to examples/perfex

  to have it list the current CPU's available events.

- Added 'set of events' descriptors for each supported CPU type

  to the library, and changed it to be a standard archive file.

- Performance counter interrupts now work in standard kernels,

  starting with kernel 2.4.10. Updated README.

Version 2.1.3, 2001-09-13

- Fixed a problem which prevented compiling the driver as a module

  in kernels older than 2.2.20pre10 if CONFIG_KMOD was disabled.

- Cleaned up command-line option processing in perfex. It now

  uses the GNU getopt library and accepts long option names.

- Fixed a typo in perfctr-events.tab (P6's INST_DECODED was

  misspelled as INST_DECODER), and updated/corrected several

  unit mask descriptions.

- Replaced most occurrences of "VIA Cyrix III / C3" with "VIA C3".

Version 2.1.2, 2001-09-05

- Added MODULE_LICENSE() tag, for compatibility with the tainted/

  non-tainted kernel stuff being put into 2.4.9-ac and modutils.

- The VIA C3 should be supported properly now, thanks to tests run

  by Dave Jones @ SuSE which clarified some aspects of the C3.

- Minor bug fix in the perfctr interrupt assembly code.

  (Inherited from the 2.4 kernel. Fixed in 2.4.9-ac4.)

Version 2.1.1, 2001-08-28

- Fixed a bug in the finalise backpatching code, which could

  cause a kernel hang in some configurations.

- Updated for kernel 2.4.9-ac3, which required changes to

  avoid conflicts in the %cr4 access methods.

- Preliminary code to detect Pentium 4 processors with Performance

  Monitoring features available.

- Minor %cr4-related cleanups.

- Minor documentation updates.

- Added a link in OTHER to Curtis Janssen's vprof tool.