/*
* notify_self3.c - example of how you can use overflow notifications with no messages
*
* 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/ia64.
*/
#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>
#define SMPL_PERIOD 1000000000UL
static volatile unsigned long notification_received;
#define NUM_PMCS PFMLIB_MAX_PMCS
#define NUM_PMDS PFMLIB_MAX_PMDS
static pfarg_reg_t pd[NUM_PMDS];
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
sigio_handler(int n, struct siginfo *info, struct sigcontext *sc)
{
if (perfmonctl(ctx_fd, PFM_READ_PMDS, pd+1, 1) == -1) {
fatal_error("PFM_READ_PMDS: %s", strerror(errno));
}
/*
* we do not need to extract the overflow message, we know
* where it is coming from.
*/
/*
* XXX: risky to do printf() in signal handler!
*/
if (event1_name)
printf("Notification %02lu: %"PRIu64" %s\n", notification_received, pd[1].reg_value, event1_name);
else
printf("Notification %02lu:\n", notification_received);
/*
* At this point, the counter used for the sampling period has already
* be reset by the kernel because we are in non-blocking mode, self-monitoring.
*/
/*
* increment our notification counter
*/
notification_received++;
/*
* And resume monitoring
*/
if (perfmonctl(ctx_fd, PFM_RESTART,NULL, 0) == -1) {
fatal_error("PFM_RESTART: %s", strerror(errno));
}
}
/*
* infinite loop waiting for notification to get out
*/
void
busyloop(void)
{
/*
* busy loop to burn CPU cycles
*/
for(;notification_received < 40;) ;
}
int
main(int argc, char **argv)
{
pfarg_context_t ctx[1];
pfmlib_input_param_t inp;
pfmlib_output_param_t outp;
pfarg_reg_t pc[NUM_PMCS];
pfarg_load_t load_args;
pfmlib_options_t pfmlib_options;
struct sigaction act;
size_t len;
unsigned int i, num_counters;
int ret;
/*
* Initialize pfm library (required before we can use it)
*/
if (pfm_initialize() != PFMLIB_SUCCESS) {
printf("Can't initialize library\n");
exit(1);
}
/*
* Install the signal handler (SIGIO)
*/
memset(&act, 0, sizeof(act));
act.sa_handler = (sig_t)sigio_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 */
pfm_set_options(&pfmlib_options);
memset(pc, 0, sizeof(pc));
memset(ctx, 0, sizeof(ctx));
memset(&load_args, 0, sizeof(load_args));
memset(&inp,0, sizeof(inp));
memset(&outp,0, sizeof(outp));
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;
if (i > num_counters) {
i = num_counters;
printf("too many events provided (max=%d events), using first %d event(s)\n", num_counters, i);
}
/*
* set the default privilege mode for all counters:
* PFM_PLM3 : user level only
*/
inp.pfp_dfl_plm = PFM_PLM3;
/*
* how many counters we use
*/
inp.pfp_event_count = i;
/*
* how many counters we use
*/
if (i > 1) {
inp.pfp_event_count = i;
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);
}
/*
* 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));
}
/*
* when we know we are self-monitoring and we have only one context, then
* when we get an overflow we know where it is coming from. Therefore we can
* save the call to the kernel to extract the notification message. By default,
* a message is generated. The queue of messages has a limited size, therefore
* it is important to clear the queue by reading the message on overflow. Failure
* to do so may result in a queue full and you will lose notification messages.
*
* With the PFM_FL_OVFL_NO_MSG, no message will be queue, but you will still get
* the signal. Similarly, the PFM_MSG_END will be generated.
*/
ctx[0].ctx_flags = PFM_FL_OVFL_NO_MSG;
/*
* now create the context for self monitoring/per-task
*/
if (perfmonctl(0, PFM_CREATE_CONTEXT, ctx, 1) == -1 ) {
if (errno == ENOSYS) {
fatal_error("Your kernel does not have performance monitoring support!\n");
}
fatal_error("Can't create PFM context %s\n", strerror(errno));
}
ctx_fd = ctx->ctx_fd;
/*
* Now prepare the argument to initialize the PMDs and PMCS.
* We use pfp_pmc_count to determine the number of registers to
* setup. Note that this field can be >= pfp_event_count.
*/
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 < inp.pfp_event_count; i++) {
pd[i].reg_num = pc[i].reg_num;
}
/*
* We want to get notified when the counter used for our first
* event overflows
*/
pc[0].reg_flags |= PFM_REGFL_OVFL_NOTIFY;
pc[0].reg_reset_pmds[0] |= 1UL << outp.pfp_pmcs[1].reg_num;
/*
* we arm the first counter, such that it will overflow
* after SMPL_PERIOD events have been observed
*/
pd[0].reg_value = (~0UL) - SMPL_PERIOD + 1;
pd[0].reg_long_reset = (~0UL) - SMPL_PERIOD + 1;
pd[0].reg_short_reset = (~0UL) - SMPL_PERIOD + 1;
/*
* 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 than counting monitors.
*/
if (perfmonctl(ctx_fd, PFM_WRITE_PMCS, pc, outp.pfp_pmc_count) == -1) {
fatal_error("perfmonctl error PFM_WRITE_PMCS errno %d\n",errno);
}
if (perfmonctl(ctx_fd, PFM_WRITE_PMDS, pd, inp.pfp_event_count) == -1) {
fatal_error("perfmonctl error PFM_WRITE_PMDS errno %d\n",errno);
}
/*
* we want to monitor ourself
*/
load_args.load_pid = getpid();
if (perfmonctl(ctx_fd, PFM_LOAD_CONTEXT, &load_args, 1) == -1) {
fatal_error("perfmonctl error PFM_WRITE_PMDS 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));
}
/*
* Let's roll now
*/
pfm_self_start(ctx_fd);
busyloop();
pfm_self_stop(ctx_fd);
/*
* free our context
*/
close(ctx_fd);
return 0;
}