/*
* smpl_core_pebs.c - Intel Core processor PEBS example
*
* Copyright (c) 2006 Hewlett-Packard Development Company, L.P.
* Contributed by Stephane Eranian <eranian@hpl.hp.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* This file is part of libpfm, a performance monitoring support library for
* applications on Linux.
*/
#include <sys/types.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <syscall.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/ptrace.h>
#include <sys/mman.h>
#include <perfmon/perfmon.h>
#include <perfmon/perfmon_pebs_core_smpl.h>
#include <perfmon/pfmlib.h>
#include <perfmon/pfmlib_core.h>
#include <perfmon/pfmlib_intel_atom.h>
#include "../detect_pmcs.h"
#define SMPL_EVENT "INST_RETIRED:ANY_P" /* not all events support PEBS */
#define NUM_PMCS 16
#define NUM_PMDS 16
#define SMPL_PERIOD 100000ULL /* must not use more bits than actual HW counter width */
typedef pfm_pebs_core_smpl_hdr_t smpl_hdr_t;
typedef pfm_pebs_core_smpl_entry_t smpl_entry_t;
typedef pfm_pebs_core_smpl_arg_t smpl_arg_t;
#define FMT_NAME PFM_PEBS_CORE_SMPL_NAME
static uint64_t collected_samples;
static void fatal_error(char *fmt,...) __attribute__((noreturn));
static void
fatal_error(char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
exit(1);
}
static void
warning(char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
}
int
child(char **arg)
{
/*
* force the task to stop before executing the first
* user level instruction
*/
ptrace(PTRACE_TRACEME, 0, NULL, NULL);
execvp(arg[0], arg);
/* not reached */
exit(1);
}
static void
process_smpl_buf(smpl_hdr_t *hdr)
{
static uint64_t last_overflow = ~0; /* initialize to biggest value possible */
static uint64_t last_count;
smpl_entry_t *ent;
uint64_t entry;
unsigned long count;
count = (hdr->ds.pebs_index - hdr->ds.pebs_buf_base)/sizeof(*ent);
if (hdr->overflows == last_overflow && last_count == count) {
warning("skipping identical set of samples %"PRIu64" = %"PRIu64"\n",
hdr->overflows, last_overflow);
return;
}
last_count = count;
last_overflow = hdr->overflows;
/*
* the beginning of the buffer does not necessarily follow the header
* due to alignement.
*/
ent = (smpl_entry_t *)((unsigned long)(hdr+1)+ hdr->start_offs);
entry = collected_samples;
while(count--) {
/*
* print some of the machine registers of each sample
*/
printf("entry %06"PRIu64" eflags:0x%08llx EAX:0x%08llx ESP:0x%08llx IP:0x%08llx\n",
entry,
(unsigned long long)ent->eflags,
(unsigned long long)ent->eax,
(unsigned long long)ent->esp,
(unsigned long long)ent->ip);
ent++;
entry++;
}
collected_samples = entry;
}
int
main(int argc, char **argv)
{
pfmlib_input_param_t inp;
pfmlib_output_param_t outp;
pfmlib_core_input_param_t mod_inp;
pfmlib_options_t pfmlib_options;
pfarg_pmd_t pd[NUM_PMDS];
pfarg_pmc_t pc[NUM_PMCS];
pfarg_ctx_t ctx;
smpl_arg_t buf_arg;
pfarg_load_t load_args;
pfarg_msg_t msg;
smpl_hdr_t *hdr;
void *buf_addr;
pid_t pid;
int ret, fd, status, type;
unsigned int i;
if (argc < 2)
fatal_error("you need to pass a program to sample\n");
if (pfm_initialize() != PFMLIB_SUCCESS)
fatal_error("libpfm intialization failed\n");
/*
* check we are on an Intel Core PMU
*/
pfm_get_pmu_type(&type);
if (type != PFMLIB_INTEL_CORE_PMU && type != PFMLIB_INTEL_ATOM_PMU)
fatal_error("This program only works with an Intel Core processor\n");
/*
* pass options to library (optional)
*/
memset(&pfmlib_options, 0, sizeof(pfmlib_options));
pfmlib_options.pfm_debug = 0; /* set to 1 for debug */
pfmlib_options.pfm_verbose = 1; /* set to 1 for verbose */
pfm_set_options(&pfmlib_options);
memset(pd, 0, sizeof(pd));
memset(pc, 0, sizeof(pc));
memset(&inp, 0, sizeof(inp));
memset(&outp, 0, sizeof(outp));
memset(&mod_inp, 0, sizeof(mod_inp));
memset(&ctx, 0, sizeof(ctx));
memset(&buf_arg, 0, sizeof(buf_arg));
memset(&load_args, 0, sizeof(load_args));
/*
* search for our sampling event
*/
if (pfm_find_full_event(SMPL_EVENT, &inp.pfp_events[0]) != PFMLIB_SUCCESS)
fatal_error("cannot find sampling event %s\n", SMPL_EVENT);
inp.pfp_event_count = 1;
inp.pfp_dfl_plm = PFM_PLM3|PFM_PLM0;
/*
* important: inform libpfm we do use PEBS
*/
mod_inp.pfp_core_pebs.pebs_used = 1;
/*
* sampling buffer parameters
*/
buf_arg.buf_size = 4*getpagesize();
/*
* sampling period cannot use more bits than HW counter can supoprt
*/
buf_arg.cnt_reset = -SMPL_PERIOD;
/*
* trigger notification (interrupt) when reached 90% of buffer
*/
buf_arg.intr_thres = (buf_arg.buf_size/sizeof(smpl_entry_t))*90/100;
/*
* create context and sampling buffer
*/
fd = pfm_create_context(&ctx, FMT_NAME, &buf_arg, sizeof(buf_arg));
if (fd == -1) {
if (errno == ENOSYS) {
fatal_error("Your kernel does not have performance monitoring support!\n");
}
fatal_error("cannot create PFM context %s, maybe you do not have the PEBS sampling format in the kernel.\nCheck /sys/kernel/perfmon/formats\n", strerror(errno));
}
/*
* map buffer into our address space
*/
buf_addr = mmap(NULL, (size_t)buf_arg.buf_size, PROT_READ, MAP_PRIVATE, fd, 0);
printf("context [%d] buffer mapped @%p\n", fd, buf_addr);
if (buf_addr == MAP_FAILED)
fatal_error("cannot mmap sampling buffer errno %d\n", errno);
hdr = (smpl_hdr_t *)buf_addr;
printf("pebs_base=0x%llx pebs_end=0x%llx index=0x%llx\n"
"intr=0x%llx version=%u.%u\n"
"entry_size=%zu ds_size=%zu\n",
(unsigned long long)hdr->ds.pebs_buf_base,
(unsigned long long)hdr->ds.pebs_abs_max,
(unsigned long long)hdr->ds.pebs_index,
(unsigned long long)hdr->ds.pebs_intr_thres,
PFM_VERSION_MAJOR(hdr->version),
PFM_VERSION_MINOR(hdr->version),
sizeof(smpl_entry_t),
sizeof(hdr->ds));
if (PFM_VERSION_MAJOR(hdr->version) < 1)
fatal_error("invalid buffer format version\n");
/*
* get which PMC registers are available
*/
detect_unavail_pmcs(fd, &inp.pfp_unavail_pmcs);
/*
* let libpfm figure out how to assign event onto PMU registers
*/
if (pfm_dispatch_events(&inp, &mod_inp, &outp, NULL) != PFMLIB_SUCCESS)
fatal_error("cannot assign event %s\n", SMPL_EVENT);
/*
* propagate PMC setup from libpfm to perfmon
*/
for (i=0; i < outp.pfp_pmc_count; i++) {
pc[i].reg_num = outp.pfp_pmcs[i].reg_num;
pc[i].reg_value = outp.pfp_pmcs[i].reg_value;
/*
* must disable 64-bit emulation on the PMC0 counter
* PMC0 is the only counter useable with PEBS. We must disable
* 64-bit emulation to avoid getting interrupts for each
* sampling period, PEBS takes care of this part.
*
* This is obsolete with 2.6.30
*/
if (pc[i].reg_num == 0)
pc[i].reg_flags = PFM_REGFL_NO_EMUL64;
}
/*
* propagate PMD set from libpfm to perfmon
*/
for (i=0; i < outp.pfp_pmd_count; i++)
pd[i].reg_num = outp.pfp_pmds[i].reg_num;
/*
* setup sampling period for first counter
* we want notification on overflow, i.e., when buffer is full
*/
pd[0].reg_flags = PFM_REGFL_OVFL_NOTIFY;
pd[0].reg_value = -SMPL_PERIOD;
pd[0].reg_long_reset = -SMPL_PERIOD;
pd[0].reg_short_reset = -SMPL_PERIOD;
/*
* Now program the registers
*/
if (pfm_write_pmcs(fd, pc, outp.pfp_pmc_count) == -1)
fatal_error("pfm_write_pmcs error errno %d\n",errno);
if (pfm_write_pmds(fd, pd, outp.pfp_pmd_count) == -1)
fatal_error("pfm_write_pmds error errno %d\n",errno);
signal(SIGCHLD, SIG_IGN);
/*
* Create the child task
*/
if ((pid=fork()) == -1) fatal_error("Cannot fork process\n");
/*
* In order to get the PFM_END_MSG message, it is important
* to ensure that the child task does not inherit the file
* descriptor of the context. By default, file descriptor
* are inherited during exec(). We explicitely close it
* here. We could have set it up through fcntl(FD_CLOEXEC)
* to achieve the same thing.
*/
if (pid == 0) {
close(fd);
child(argv+1);
}
/*
* wait for the child to exec
*/
waitpid(pid, &status, WUNTRACED);
/*
* process is stopped at this point
*/
if (WIFEXITED(status)) {
warning("task %s [%d] exited already status %d\n", argv[1], pid, WEXITSTATUS(status));
goto terminate_session;
}
/*
* attach the context to child
*/
load_args.load_pid = pid;
if (pfm_load_context(fd, &load_args) == -1)
fatal_error("pfm_load_context error errno %d\n",errno);
/*
* start monitoring
*/
if (pfm_start(fd, NULL) == -1)
fatal_error("pfm_start error errno %d\n",errno);
/*
* detach child. Side effect includes
* activation of monitoring.
*/
ptrace(PTRACE_DETACH, pid, NULL, 0);
/*
* core loop
*/
for(;;) {
/*
* wait for overflow/end notification messages
*/
ret = read(fd, &msg, sizeof(msg));
if (ret == -1) {
if(ret == -1 && errno == EINTR) {
warning("read interrupted, retrying\n");
continue;
}
fatal_error("cannot read perfmon msg: %s\n", strerror(errno));
}
switch(msg.type) {
case PFM_MSG_OVFL: /* the sampling buffer is full */
process_smpl_buf(hdr);
/*
* reactivate monitoring once we are done with the samples
*
* Note that this call can fail with EBUSY in non-blocking mode
* as the task may have disappeared while we were processing
* the samples.
*/
if (pfm_restart(fd) == -1) {
if (errno != EBUSY)
fatal_error("pfm_restart error errno %d\n",errno);
else
warning("pfm_restart: task has probably terminated \n");
}
break;
case PFM_MSG_END: /* monitored task terminated */
warning("task terminated\n");
goto terminate_session;
default: fatal_error("unknown message type %d\n", msg.type);
}
}
terminate_session:
/*
* cleanup child
*/
wait4(pid, &status, 0, NULL);
/*
* check for any leftover samples
*/
process_smpl_buf(hdr);
printf("collected samples %"PRIu64"n", collected_samples);
/*
* close context
*/
close(fd);
/*
* unmap sampling buffer and actually free the perfmon context
*/
munmap(buf_addr, (size_t)buf_arg.buf_size);
return 0;
}