/*
* smpl_nhm_lbr.c - Intel Nehalem LBR sampling
*
* Copyright (c) 2008 Google, Inc
* Contributed by Stephane Eranian <eranian@gmail.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.
*/
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <stdarg.h>
#include <stdint.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <setjmp.h>
#include <perfmon/pfmlib.h>
#include <perfmon/pfmlib_intel_nhm.h>
#include <perfmon/perfmon.h>
#include <perfmon/perfmon_dfl_smpl.h>
#include "../detect_pmcs.h"
#define SAMPLING_PERIOD 100000
#define EVENT_NAME "br_inst_retired:all_branches"
typedef pfm_dfl_smpl_arg_t smpl_fmt_arg_t;
typedef pfm_dfl_smpl_hdr_t smpl_hdr_t;
typedef pfm_dfl_smpl_entry_t smpl_entry_t;
typedef pfm_dfl_smpl_arg_t smpl_arg_t;
#define FMT_NAME PFM_DFL_SMPL_NAME
#define NUM_PMCS PFMLIB_MAX_PMCS
#define NUM_PMDS PFMLIB_MAX_PMDS
static jmp_buf jbuf;
static uint64_t collected_samples, collected_partial, ovfl_count;
static void fatal_error(char *fmt,...) __attribute__((noreturn));
#define BPL (sizeof(uint64_t)<<3)
#define LBPL 6
static void handler (int n)
{
longjmp(jbuf, 1);
}
static inline void pfm_bv_set(uint64_t *bv, uint16_t rnum)
{
bv[rnum>>LBPL] |= 1UL << (rnum&(BPL-1));
}
static void
warning(char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
}
static void
fatal_error(char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
exit(1);
}
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;
size_t pos, count, entry_size;
uint64_t entry, *reg;
uint64_t tos, i;
if (hdr->hdr_overflows == last_overflow && hdr->hdr_count == last_count) {
warning("skipping identical set of samples %"PRIu64" = %"PRIu64"\n",
hdr->hdr_overflows, last_overflow);
return;
}
/*
* 33 = 32 LBR registers + LBR_TOS
*/
entry_size = sizeof(smpl_entry_t) + 33 * sizeof(uint64_t);
count = hdr->hdr_count;
ent = (smpl_entry_t *)(hdr+1);
pos = (unsigned long)ent;
entry = collected_samples;
while(count--) {
printf("entry %"PRIu64" PID:%d TID:%d CPU:%d LAST_VAL:%"PRIu64" OVFL:%u IIP:0x%llx\n",
entry,
ent->tgid,
ent->pid,
ent->cpu,
-ent->last_reset_val,
ent->ovfl_pmd,
(unsigned long long)ent->ip);
/*
* TOS is pmd31 and comes first
* TOs points to most recent entry
*/
reg = (uint64_t *)(ent+1);
tos = reg[0] * 2;
/*
* i points to oldest entry, the one to print first
*/
i = (tos + 2) % 32;
/*
* iterate over the 16 branches printing src -> dst
*/
while (i != tos) {
printf("0x%016"PRIx64" -> 0x%016"PRIx64"\n",
reg[1+i],
reg[1+i+1]);
i = (i + 2) % 32;
}
pos += entry_size;
ent = (smpl_entry_t *)pos;
entry++;
}
collected_samples = entry;
last_overflow = hdr->hdr_overflows;
if (last_count != hdr->hdr_count && (last_count || last_overflow == 0))
collected_partial += hdr->hdr_count;
last_count = hdr->hdr_count;
}
int
mainloop(char **arg)
{
smpl_hdr_t *hdr;
pfarg_ctx_t ctx;
smpl_arg_t buf_arg;
pfmlib_input_param_t inp;
pfmlib_nhm_input_param_t mod_inp;
pfmlib_output_param_t outp;
pfarg_pmd_t pd[NUM_PMDS];
pfarg_pmc_t pc[NUM_PMCS];
pfarg_load_t load_args;
pfarg_msg_t msg;
void *buf_addr;
pid_t pid;
int i, status, ret, fd;
/*
* intialize all locals
*/
memset(&ctx, 0, sizeof(ctx));
memset(&buf_arg, 0, sizeof(buf_arg));
memset(&inp,0, sizeof(inp));
memset(&outp,0, sizeof(outp));
memset(pd, 0, sizeof(pd));
memset(pc, 0, sizeof(pc));
memset(&load_args, 0, sizeof(load_args));
memset(&mod_inp, 0, sizeof(mod_inp));
ret = pfm_find_full_event(EVENT_NAME, &inp.pfp_events[0]);
if (ret != PFMLIB_SUCCESS)
fatal_error("cannot find event %s\n", EVENT_NAME);
/*
* set the privilege mode:
* PFM_PLM3 : user level
* PFM_PLM0 : kernel level
*/
inp.pfp_dfl_plm = PFM_PLM3;
/*
* how many counters we use
*/
inp.pfp_event_count = 1;
mod_inp.pfp_nhm_lbr.lbr_used = 1;
mod_inp.pfp_nhm_lbr.lbr_plm = 0; /* inherit from pfp_dfl_plm */
/*
* setup LBR filter
*
* By default all types of branches are captured
*
* it is possible to filter out some types of branches using
* the macros in pfmlib_intel_nhm.c.
*
* for instance, to only capture nears calls, you do:
*
* lbr_filter = PFM_NHM_LBR_NEAR_REL_CALL
*/
mod_inp.pfp_nhm_lbr.lbr_filter = 0;
/*
* the size of the buffer is indicated in bytes (not entries).
*
* The kernel will record into the buffer up to a certain point.
* No partial samples are ever recorded.
*/
buf_arg.buf_size = 4 * getpagesize();
/*
* now create our perfmon context.
*/
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\n", strerror(errno));
}
detect_unavail_pmcs(fd, &inp.pfp_unavail_pmcs);
/*
* let the library figure out the values for the PMCS
*/
if ((ret=pfm_dispatch_events(&inp, &mod_inp, &outp, NULL)) != PFMLIB_SUCCESS)
fatal_error("cannot configure events: %s\n", pfm_strerror(ret));
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;
}
/*
* we use only one counter
*/
pd[0].reg_num = outp.pfp_pmds[0].reg_num;
pd[0].reg_flags = PFM_REGFL_OVFL_NOTIFY;
/*
* add 2 x 16 LBR entries + LBR_TOS to smpl_pmds
*/
for(i=31; i < 64; i++)
pfm_bv_set(pd[0].reg_smpl_pmds, i);
/*
* we need to reset LBR after each sample to be able to determine
* whether or not we get new data
*
* LBR_TOS(PMD31) is read-only, it is not included in reset_pmds
*/
for(i=32; i < 64; i++)
pfm_bv_set(pd[0].reg_reset_pmds, i);
/*
* set sampling periods
*/
pd[0].reg_value = - SAMPLING_PERIOD;
pd[0].reg_short_reset = - SAMPLING_PERIOD;
pd[0].reg_long_reset = - SAMPLING_PERIOD;
/*
* prepare context structure.
*/
/*
* retrieve the virtual address at which the sampling
* buffer has been mapped
*/
buf_addr = mmap(NULL, (size_t)buf_arg.buf_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (buf_addr == MAP_FAILED)
fatal_error("cannot mmap sampling buffer: %s\n", strerror(errno));
printf("buffer mapped @%p\n", buf_addr);
hdr = (smpl_hdr_t *)buf_addr;
printf("hdr_cur_offs=%llu version=%u.%u\n",
(unsigned long long)hdr->hdr_cur_offs,
PFM_VERSION_MAJOR(hdr->hdr_version),
PFM_VERSION_MINOR(hdr->hdr_version));
if (PFM_VERSION_MAJOR(hdr->hdr_version) < 1)
fatal_error("invalid buffer format version\n");
/*
* program the PMCs
*/
if (pfm_write_pmcs(fd, pc, outp.pfp_pmc_count))
fatal_error("pfm_write_pmcs error errno %d\n",errno);
/*
* program our counter
*/
if (pfm_write_pmds(fd, pd, 1))
fatal_error("pfm_write_pmds error errno %d\n",errno);
/*
* create the child task
*/
if ((pid=fork()) == -1)
fatal_error("Cannot fork process\n");
/*
* create child
* make sure child does not inherit the file descriptor
*/
if (pid == 0) {
close(fd);
child(arg);
}
/*
* 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", arg[0], pid, WEXITSTATUS(status));
goto terminate_session;
}
/*
* attach context to stopped task
*/
load_args.load_pid = pid;
if (pfm_load_context (fd, &load_args))
fatal_error("pfm_load_context error errno %d\n",errno);
/*
* activate monitoring for stopped task.
* (nothing will be measured at this point
*/
if (pfm_start(fd, NULL))
fatal_error("pfm_start error errno %d\n",errno);
/*
* detach child. Side effect includes
* activation of monitoring.
*/
ptrace(PTRACE_DETACH, pid, NULL, 0);
signal(SIGCHLD, handler);
if (setjmp(jbuf) == 1)
goto terminate_session;
/*
* core loop
*/
for(;;) {
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));
}
if (msg.type == PFM_MSG_OVFL) {
process_smpl_buf(hdr);
ovfl_count++;
/*
* 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)) {
if (errno != EBUSY)
fatal_error("pfm_restart error errno %d\n",errno);
}
}
}
terminate_session:
/*
* cleanup child
*/
wait4(pid, &status, 0, NULL);
/*
* check for any leftover samples
*/
process_smpl_buf(hdr);
close(fd);
ret = munmap(hdr, (size_t)buf_arg.buf_size);
if (ret)
fatal_error("cannot unmap buffer: %s\n", strerror(errno));
printf("%"PRIu64" samples (%"PRIu64" in partial buffer) collected in %"PRIu64" buffer overflows\n",
collected_samples,
collected_partial,
ovfl_count);
return 0;
}
int
main(int argc, char **argv)
{
pfmlib_options_t pfmlib_options;
int ret;
if (argc == 1)
fatal_error("You must specify a command to execute\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);
/*
* Initialize pfm library (required before we can use it)
*/
ret = pfm_initialize();
if (ret != PFMLIB_SUCCESS)
fatal_error("Cannot initialize library: %s\n", pfm_strerror(ret));
return mainloop(argv+1);
}