/*
* notify_self2.c - example of how you can use overflow notifications with F_SETSIG
*
* Copyright (c) 2002-2006 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.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE /* for getline */
#endif
#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 <fcntl.h>
#include <perfmon/perfmon.h>
#include <perfmon/pfmlib.h>
#include "detect_pmcs.h"
#define SMPL_PERIOD 1000000000ULL
static volatile unsigned long notification_received;
#define NUM_PMCS PFMLIB_MAX_PMCS
#define NUM_PMDS PFMLIB_MAX_PMDS
static pfarg_pmr_t pdx[1];
static int ctx_fd;
static char *event1_name;
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);
}
static void
sigio_handler(int n, struct siginfo *info, void *data)
{
pfarg_msg_t msg;
int fd;
int r =0;
if (info == NULL)
fatal_error("info is NULL\n");
fd = info->si_fd;
if (fd != ctx_fd)
fatal_error("handler does not get valid file descriptor\n");
if (event1_name && pfm_read(fd, 0, PFM_RW_PMD, pdx, sizeof(pdx)))
fatal_error("pfm_read: %s", strerror(errno));
retry:
r = read(fd, &msg, sizeof(msg));
if (r != sizeof(msg)) {
if(r == -1 && errno == EINTR) {
warning("read interrupted, retrying\n");
goto retry;
}
fatal_error("cannot read overflow message: %s\n", strerror(errno));
}
if (msg.type != PFM_MSG_OVFL)
fatal_error("unexpected msg type: %d\n",msg.type);
/*
* increment our notification counter
*/
notification_received++;
/*
* XXX: risky to do printf() in signal handler!
*/
if (event1_name)
printf("Notification %lu: %"PRIu64" %s\n", notification_received, pdx[0].reg_value, event1_name);
else
printf("Notification %lu\n", notification_received);
/*
* And resume monitoring
*/
if (pfm_set_state(fd, 0, PFM_ST_RESTART))
fatal_error("pfm_set_state(restart): %d\n", errno);
}
/*
* infinite loop waiting for notification to get out
*/
void
busyloop(void)
{
/*
* busy loop to burn CPU cycles
*/
for(;notification_received < 20;) ;
}
#define BPL (sizeof(uint64_t)<<3)
#define LBPL 6
static inline void pfm_bv_set(uint64_t *bv, uint16_t rnum)
{
bv[rnum>>LBPL] |= 1UL << (rnum&(BPL-1));
}
int
main(int argc, char **argv)
{
pfmlib_input_param_t inp;
pfmlib_output_param_t outp;
pfarg_pmr_t pc[NUM_PMCS];
pfarg_pmd_attr_t pd[NUM_PMDS];
pfarg_sinfo_t sif;
pfmlib_options_t pfmlib_options;
struct sigaction act;
unsigned int i, num_counters;
size_t len;
int ret;
/*
* 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));
/*
* Install the signal handler (SIGIO)
*
* SA_SIGINFO required on some platforms
* to get siginfo passed to handler.
*/
memset(&act, 0, sizeof(act));
act.sa_handler = (sig_t)sigio_handler;
act.sa_flags = SA_SIGINFO;
sigaction (SIGIO, &act, 0);
memset(pc, 0, sizeof(pc));
memset(pd, 0, sizeof(pd));
memset(&inp,0, sizeof(inp));
memset(&outp,0, sizeof(outp));
memset(&sif,0, sizeof(sif));
pfm_get_num_counters(&num_counters);
if (pfm_get_cycle_event(&inp.pfp_events[0]) != PFMLIB_SUCCESS)
fatal_error("cannot find cycle event\n");
if (pfm_get_inst_retired_event(&inp.pfp_events[1]) != PFMLIB_SUCCESS)
fatal_error("cannot find inst retired event\n");
i = 2;
/*
* set the default privilege mode for all counters:
* PFM_PLM3 : user level only
*/
inp.pfp_dfl_plm = PFM_PLM3;
if (i > num_counters) {
i = num_counters;
printf("too many events provided (max=%d events), using first %d event(s)\n", num_counters, i);
}
inp.pfp_event_count = i;
/*
* how many counters we use
*/
if (i > 1) {
pfm_get_max_event_name_len(&len);
event1_name = malloc(len+1);
if (event1_name == NULL)
fatal_error("cannot allocate event name\n");
pfm_get_full_event_name(&inp.pfp_events[1], event1_name, len+1);
}
/*
* now create the session for self monitoring/per-task
*/
ctx_fd = pfm_create(0, &sif);
if (ctx_fd == -1) {
if (errno == ENOSYS) {
fatal_error("Your kernel does not have performance monitoring support!\n");
}
fatal_error("cannot create session %s\n", strerror(errno));
}
/*
* build the pfp_unavail_pmcs bitmask by looking
* at what perfmon has available. It is not always
* the case that all PMU registers are actually available
* to applications. For instance, on IA-32 platforms, some
* registers may be reserved for the NMI watchdog timer.
*
* With this bitmap, the library knows which registers NOT to
* use. Of source, it is possible that no valid assignement may
* be possible if certina PMU registers are not available.
*/
detect_unavail_pmu_regs(&sif, &inp.pfp_unavail_pmcs, NULL);
/*
* let the library figure out the values for the PMCS
*/
if ((ret=pfm_dispatch_events(&inp, NULL, &outp, NULL)) != PFMLIB_SUCCESS)
fatal_error("Cannot configure events: %s\n", pfm_strerror(ret));
/*
* Now prepare the argument to initialize the PMDs and PMCS.
*/
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;
}
for (i=0; i < outp.pfp_pmd_count; i++)
pd[i].reg_num = outp.pfp_pmds[i].reg_num;
/*
* We want to get notified when the counter used for our first
* event overflows
*/
pd[0].reg_flags |= PFM_REGFL_OVFL_NOTIFY;
if (inp.pfp_event_count > 1) {
pfm_bv_set(pd[0].reg_reset_pmds, pd[1].reg_num);
pdx[0].reg_num = pd[1].reg_num;
}
/*
* we arm the first counter, such that it will overflow
* after SMPL_PERIOD events have been observed
*/
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(ctx_fd, 0, PFM_RW_PMC, pc, outp.pfp_pmc_count * sizeof(*pc)))
fatal_error("pfm_write error errno %d\n",errno);
if (pfm_write(ctx_fd, 0, PFM_RW_PMD_ATTR, pd, outp.pfp_pmd_count * sizeof(*pd)))
fatal_error("pfm_write(PMD) error errno %d\n",errno);
/*
* we want to monitor ourself
*/
if (pfm_attach(ctx_fd, 0, getpid()))
fatal_error("pfm_attach error errno %d\n",errno);
/*
* setup asynchronous notification on the file descriptor
*/
ret = fcntl(ctx_fd, F_SETFL, fcntl(ctx_fd, F_GETFL, 0) | O_ASYNC);
if (ret == -1)
fatal_error("cannot set ASYNC: %s\n", strerror(errno));
/*
* get ownership of the descriptor
*/
ret = fcntl(ctx_fd, F_SETOWN, getpid());
if (ret == -1)
fatal_error("cannot setown: %s\n", strerror(errno));
#ifndef _GNU_SOURCE
#error "this program must be compiled with -D_GNU_SOURCE"
#else
/*
* when you explicitely declare that you want a particular signal,
* even with you use the default signal, the kernel will send more
* information concerning the event to the signal handler.
*
* In particular, it will send the file descriptor from which the
* event is originating which can be quite useful when monitoring
* multiple tasks from a single thread.
*/
ret = fcntl(ctx_fd, F_SETSIG, SIGIO);
if (ret == -1)
fatal_error("cannot setsig: %s\n", strerror(errno));
#endif
/*
* Let's roll now
*/
if (pfm_set_state(ctx_fd, 0, PFM_ST_START))
fatal_error("pfm_set_state(start) error errno %d\n", errno);
busyloop();
if (pfm_set_state(ctx_fd, 0, PFM_ST_STOP))
fatal_error("pfm_set_state(stop) error errno %d\n", errno);
/*
* destroy our context
*/
close(ctx_fd);
if (event1_name)
free(event1_name);
return 0;
}