/*
* self_smpl.c - example of self sampling using a kernel samplig buffer
*
* Copyright (c) 2009 Google, Inc
* Contributed by Stephane Eranian <eranian@gmail.com>
*
* Based on mont_dear.c from:
* Copyright (c) 2005-2006 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 <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <inttypes.h>
#include <err.h>
#include <perfmon/pfmlib.h>
#include <perfmon/perfmon.h>
#include <perfmon/perfmon_dfl_smpl.h>
#define SMPL_PERIOD (2400000)
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;
static int fd;
static void *smpl_vaddr;
static size_t entry_size;
long
do_test(unsigned long size)
{
unsigned long i, sum = 0;
int *array;
array = (int *)malloc(size * sizeof(int));
if (array == NULL ) {
printf("line = %d No memory available!\n", __LINE__);
exit(1);
}
for(i=0; i<size; i++) {
array[i]=1;
}
free(array);
return sum;
}
static void
process_smpl_buffer(void)
{
static uint64_t last_ovfl = ~0UL;
static uint64_t smpl_entry = 0;
smpl_hdr_t *hdr;
smpl_entry_t *ent;
unsigned long pos;
uint64_t count;
hdr = (smpl_hdr_t *)smpl_vaddr;
/*
* check that we are not diplaying the previous set of samples again.
* Required to take care of the last batch of samples.
*/
if (hdr->hdr_overflows <= last_ovfl && last_ovfl != ~0UL) {
printf("skipping identical set of samples %"PRIu64" <= %"PRIu64"\n", hdr->hdr_overflows, last_ovfl);
return;
}
pos = (unsigned long)(hdr+1);
count = hdr->hdr_count;
/*
* walk through all the entries recored in the buffer
*/
while(count--) {
ent = (smpl_entry_t *)pos;
/*
* print entry header
*/
printf("Entry %"PRIu64" PID:%d TID:%d CPU:%d STAMP:0x%"PRIx64" IIP:0x%016"PRIx64"\n",
smpl_entry++,
ent->tgid,
ent->pid,
ent->cpu,
ent->tstamp,
ent->ip);
/*
* move to next entry
*/
pos += entry_size;
}
}
static void
overflow_handler(int n, struct siginfo *info, struct sigcontext *sc)
{
process_smpl_buffer();
/*
* And resume monitoring
*/
if (pfm_restart(fd))
errx(1, "pfm_restart");
}
int
main(void)
{
pfarg_pmd_t pd[8];
pfarg_pmc_t pc[8];
pfmlib_input_param_t inp;
pfmlib_output_param_t outp;
pfarg_ctx_t ctx;
pfarg_load_t load_args;
smpl_arg_t buf_arg;
pfmlib_options_t pfmlib_options;
unsigned long nloop = 10000;
struct sigaction act;
unsigned int i;
int ret;
/*
* Initialize pfm library (required before we can use it)
*/
if (pfm_initialize() != PFMLIB_SUCCESS)
errx(1, "cannot initialize library\n");
/*
* Install the overflow handler (SIGIO)
*/
memset(&act, 0, sizeof(act));
act.sa_handler = (sig_t)overflow_handler;
sigaction (SIGIO, &act, 0);
/*
* 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 debug */
pfm_set_options(&pfmlib_options);
memset(pd, 0, sizeof(pd));
memset(pc, 0, sizeof(pc));
memset(pc, 0, sizeof(pc));
memset(&ctx, 0, sizeof(ctx));
memset(&buf_arg, 0, sizeof(buf_arg));
memset(&load_args, 0, sizeof(load_args));
/*
* prepare parameters to library. we don't use any Itanium
* specific features here. so the pfp_model is NULL.
*/
memset(&inp,0, sizeof(inp));
memset(&outp,0, sizeof(outp));
/*
* To count the number of occurence of this instruction, we must
* program a counting monitor with the IA64_TAGGED_INST_RETIRED_PMC8
* event.
*/
if (pfm_get_cycle_event(&inp.pfp_events[0]) != PFMLIB_SUCCESS)
errx(1, "cannot find cycle event\n");
/*
* set the (global) privilege mode:
* PFM_PLM0 : kernel level only
*/
inp.pfp_dfl_plm = PFM_PLM3|PFM_PLM0;
/*
* how many counters we use
*/
inp.pfp_event_count = 1;
/*
* let the library figure out the values for the PMCS
*
* We use all global settings for this EAR.
*/
if ((ret=pfm_dispatch_events(&inp, NULL, &outp, NULL)) != PFMLIB_SUCCESS)
errx(1, "cannot configure events: %s\n", pfm_strerror(ret));
/*
* 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 = getpagesize();
/*
* do not generate overflow notification messages
*/
ctx.ctx_flags = PFM_FL_OVFL_NO_MSG;
/*
* now create the context for self monitoring/per-task
*/
fd = pfm_create_context(&ctx, PFM_DFL_SMPL_NAME, &buf_arg, sizeof(buf_arg));
if (fd == -1) {
if (errno == ENOSYS)
errx(1, "kernel does not have performance monitoring support!\n");
errx(1, "cannot create PFM context %s\n", strerror(errno));
}
/*
* retrieve the virtual address at which the sampling
* buffer has been mapped
*/
smpl_vaddr = mmap(NULL, (size_t)buf_arg.buf_size, PROT_READ, MAP_PRIVATE, fd, 0);
if (smpl_vaddr == MAP_FAILED)
errx(1, "cannot mmap sampling buffer errno %d\n", errno);
printf("Sampling buffer mapped at %p\n", smpl_vaddr);
/*
* Now prepare the argument to initialize the PMDs and PMCS.
* We must pfp_pmc_count to determine the number of PMC to intialize.
* We must use pfp_event_count to determine the number of PMD to initialize.
* Some events causes extra PMCs to be used, so pfp_pmc_count may be >= pfp_event_count.
*
* This step is new compared to libpfm-2.x. It is necessary because the library no
* longer knows about the kernel data structures.
*/
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;
}
/*
* figure out pmd mapping from output pmc
*/
for (i=0; i < outp.pfp_pmd_count; i++)
pd[i].reg_num = outp.pfp_pmds[i].reg_num;
/*
* indicate we want notification when buffer is full
*/
pd[0].reg_flags |= PFM_REGFL_OVFL_NOTIFY;
entry_size = sizeof(smpl_entry_t);
/*
* initialize the PMD and the sampling period
*/
pd[0].reg_value = - SMPL_PERIOD;
pd[0].reg_long_reset = - SMPL_PERIOD;
pd[0].reg_short_reset = - SMPL_PERIOD;
/*
* Now program the registers
*
* We don't use the save variable to indicate the number of elements passed to
* the kernel because, as we said earlier, pc may contain more elements than
* the number of events we specified, i.e., contains more thann coutning monitors.
*/
if (pfm_write_pmcs(fd, pc, outp.pfp_pmc_count))
errx(1, "pfm_write_pmcs error errno %d\n",errno);
if (pfm_write_pmds(fd, pd, outp.pfp_pmd_count))
errx(1, "pfm_write_pmds error errno %d\n",errno);
/*
* attach context to stopped task
*/
load_args.load_pid = getpid();
if (pfm_load_context(fd, &load_args))
errx(1, "pfm_load_context error errno %d\n",errno);
/*
* setup asynchronous notification on the file descriptor
*/
ret = fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_ASYNC);
if (ret == -1)
errx(1, "cannot set ASYNC: %s\n", strerror(errno));
/*
* get ownership of the descriptor
*/
ret = fcntl(fd, F_SETOWN, getpid());
if (ret == -1)
errx(1, "cannot setown: %s\n", strerror(errno));
/*
* Let's roll now.
*/
ret = pfm_start(fd, NULL);
if (ret == -1)
errx(1, "cannot pfm_start: %s\n", strerror(errno));
while(nloop--)
do_test(100000);
ret = pfm_stop(fd);
if (ret == -1)
errx(1, "cannot pfm_stop: %s\n", strerror(errno));
/*
* We must call the processing routine to cover the last entries recorded
* in the sampling buffer, i.e. which may not be full
*/
process_smpl_buffer();
/*
* let's stop this now
*/
munmap(smpl_vaddr, (size_t)buf_arg.buf_size);
close(fd);
return 0;
}