/*
* smpl_pebs.c - Unified Intel PEBS sampling example
*
* Copyright (c) 2009 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.
*
* 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 <err.h>
#include <perfmon/perfmon.h>
#include <perfmon/perfmon_pebs_smpl.h>
#include <perfmon/pfmlib.h>
#include <perfmon/pfmlib_core.h>
#include <perfmon/pfmlib_intel_nhm.h>
#include "../detect_pmcs.h"
#define SMPL_EVENT "INST_RETIRED:ANY_P" /* PEBS event on all processors */
#define NUM_PMCS 16
#define NUM_PMDS 16
#define SMPL_PERIOD 240000ULL /* must not use more bits than actual HW counter width */
typedef pfm_pebs_smpl_hdr_t smpl_hdr_t;
typedef pfm_pebs_smpl_arg_t smpl_arg_t;
#define FMT_NAME PFM_PEBS_SMPL_NAME
static uint64_t collected_samples;
static uint64_t last_overflow = ~0; /* initialize to biggest value possible */
static void (*print_entry)(uint64_t entry, void *addr);
static int maxpebs = 1; /* 1=Atom/Core, up to 4 on Nehalem */
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
print_p4_entry(uint64_t entry, void *addr)
{
pfm_pebs_p4_smpl_entry_t *ent = addr;
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);
}
static void
print_core_entry(uint64_t entry, void *addr)
{
pfm_pebs_core_smpl_entry_t *ent = addr;
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);
}
static void
print_nhm_entry(uint64_t entry, void *addr)
{
pfm_pebs_nhm_smpl_entry_t *ent = addr;
printf("entry %06"PRIu64" eflags:0x%08llx EAX:0x%08llx ESP:0x%08llx IP:0x%08llx OVFL:0x%08llx\n",
entry,
(unsigned long long)ent->eflags,
(unsigned long long)ent->eax,
(unsigned long long)ent->esp,
(unsigned long long)ent->ip,
(unsigned long long)ent->ia32_perf_global_status);
}
static void
process_smpl_buf(smpl_hdr_t *hdr)
{
static uint64_t last_count;
void *ent;
uint64_t entry;
unsigned long count;
count = hdr->count;
if (hdr->overflows == last_overflow && last_count == count) {
warnx("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 = (hdr+1);
entry = collected_samples;
while(count--) {
(*print_entry)(entry, ent);
ent += hdr->entry_size;
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 core_inp;
pfmlib_nhm_input_param_t nhm_inp;
void *mod_inp = NULL;
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)
errx(1, "you need to pass a program to sample");
if (pfm_initialize() != PFMLIB_SUCCESS)
errx(1, "libpfm intialization failed");
memset(&core_inp, 0, sizeof(core_inp));
memset(&nhm_inp, 0, sizeof(nhm_inp));
/*
* check we are on an Intel Core PMU
*/
pfm_get_pmu_type(&type);
switch(type) {
case PFMLIB_INTEL_CORE_PMU:
case PFMLIB_INTEL_ATOM_PMU:
print_entry = print_core_entry;
core_inp.pfp_core_pebs.pebs_used = 1;
mod_inp = &core_inp;
break;
case PFMLIB_INTEL_NHM_PMU:
print_entry = print_nhm_entry;
nhm_inp.pfp_nhm_pebs.pebs_used = 1;
mod_inp = &nhm_inp;
break;
case PFMLIB_PENTIUM4_PMU:
print_entry = print_p4_entry;
break;
default:
errx(1, "PMU model does not have PEBS support");
}
/*
* 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(&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)
errx(1, "cannot find sampling event %s", SMPL_EVENT);
for(i=1; i < maxpebs; i++)
inp.pfp_events[i] = inp.pfp_events[0];
inp.pfp_event_count = i;
inp.pfp_dfl_plm = PFM_PLM3|PFM_PLM0;
/*
* sampling buffer parameters
*/
buf_arg.buf_size = 2 * getpagesize();
for(i=0; i < maxpebs; i++)
buf_arg.cnt_reset[i] = -SMPL_PERIOD;
/*
* create context and sampling buffer
*/
fd = pfm_create_context(&ctx, FMT_NAME, &buf_arg, sizeof(buf_arg));
if (fd == -1) {
if (errno == ENOSYS) {
errx(1, "Your kernel does not have performance monitoring support!\n");
}
err(1, "cannot create session, maybe you do not have the PEBS"
" sampling format in the kernel. You need perfmon_pebs_smpl."
"\nCheck /sys/kernel/perfmon/formats");
}
/*
* map buffer into our address space
*/
buf_addr = mmap(NULL, (size_t)buf_arg.buf_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (buf_addr == MAP_FAILED)
err(1, "cannot mmap sampling buffer");
printf("context [%d] buffer mapped @%p\n", fd, buf_addr);
hdr = (smpl_hdr_t *)buf_addr;
printf("pebs_start=%p pebs_end=%p version=%u.%u.%u entry_size=%u\n",
hdr+1,
hdr+1,
(hdr->version >> 16) & 0xff,
(hdr->version >> 8) & 0xff,
hdr->version & 0xff,
hdr->entry_size);
printf("max PEBS entries: %zu\n", (size_t)hdr->pebs_size / hdr->entry_size);
if (((hdr->version >> 16) & 0xff) < 1)
errx(1, "invalid buffer format version");
/*
* 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)
errx(1, "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.
*/
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
*/
for(i=0; i < maxpebs; i++) {
pd[i].reg_flags = PFM_REGFL_OVFL_NOTIFY;
pd[i].reg_value = -SMPL_PERIOD;
pd[i].reg_long_reset = -SMPL_PERIOD;
pd[i].reg_short_reset = -SMPL_PERIOD;
}
/*
* Now program the registers
*/
if (pfm_write_pmcs(fd, pc, outp.pfp_pmc_count) == -1)
err(1, "pfm_write_pmcs error");
if (pfm_write_pmds(fd, pd, outp.pfp_pmd_count) == -1)
err(1, "pfm_write_pmds error");
signal(SIGCHLD, SIG_IGN);
/*
* Create the child task
*/
if ((pid=fork()) == -1)
err(1, "cannot fork process");
/*
* 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)) {
warnx("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)
err(1, "pfm_load_context error");
/*
* start monitoring
*/
if (pfm_start(fd, NULL) == -1)
err(1, "pfm_start error");
/*
* 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) {
warnx("read interrupted, retrying");
continue;
}
err(1, "cannot read perfmon msg");
}
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)
err(1, "pfm_restart error");
else
warnx("pfm_restart: task has probably terminated \n");
}
break;
case PFM_MSG_END: /* monitored task terminated */
warnx("TASK terminated");
goto terminate_session;
default:
errx(1, "unknown message type %d", msg.type);
}
}
terminate_session:
/*
* cleanup child
*/
wait4(pid, &status, 0, NULL);
/*
* check for any leftover samples
*/
process_smpl_buf(hdr);
printf("collected samples %"PRIu64", %"PRIu64" overflows\n",
collected_samples, last_overflow);
/*
* close context
*/
close(fd);
/*
* unmap sampling buffer and actually free the perfmon context
*/
munmap(buf_addr, (size_t)buf_arg.buf_size);
return 0;
}