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/*
* Copyright (C) 2016 Julien Desfossez <jdesfossez@efficios.com>
*
* SPDX-License-Identifier: GPL-2.0-only
*
*/
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <linux/perf_event.h>
#include <perfmon/perf_event.h>
#include <perfmon/pfmlib_perf_event.h>
int main(int argc, char **argv)
{
int ret, fd;
/* pfm query objects */
pfm_perf_encode_arg_t pencoder;
pfm_event_info_t info;
/* Perf event object to be populated by libpfm */
struct perf_event_attr attr;
if (argc != 2) {
fprintf(stderr, "Usage: %s <pmu counter to find>\n"
"ex: %s UNHALTED_REFERENCE_CYCLES\n"
"Returns the event raw number if found and actionable with"
"return code 0.\n"
"If not found returns 1,"
"If not actionable return 2,"
"on error returns 255\n",
argv[0], argv[0]);
ret = -1;
goto end;
}
/* Initialize perf_event_attr. */
memset(&attr, 0, sizeof(struct perf_event_attr));
/* Initialize libpfm encoder structure. */
memset(&pencoder, 0, sizeof(pencoder));
pencoder.size = sizeof(pfm_perf_encode_arg_t);
/* Initialize libpfm event info structure. */
memset(&info, 0, sizeof(info));
info.size = sizeof(info);
/* Prepare the encoder for query. */
pencoder.attr = &attr; /* Set the perf_event_attr pointer. */
pencoder.fstr = NULL; /* Not interested by the fully qualified event string. */
ret = pfm_initialize();
if (ret != PFM_SUCCESS) {
fprintf(stderr, "Failed to initialise libpfm: %s",
pfm_strerror(ret));
ret = 255;
goto end;
}
ret = pfm_get_os_event_encoding(argv[1],
PFM_PLM0 | PFM_PLM1 | PFM_PLM2 | PFM_PLM3,
PFM_OS_PERF_EVENT, &pencoder);
if (ret != PFM_SUCCESS) {
fprintf(stderr, "libpfm: error pfm_get_os_event_encoding: %s\n",
pfm_strerror(ret));
ret = 1;
goto end;
}
/*
* Query the raw code for later use. Do it now to simplify error
* management.
*/
ret = pfm_get_event_info(pencoder.idx, PFM_OS_NONE, &info);
if (ret != PFM_SUCCESS) {
fprintf(stderr, "libpfm: error pfm_get_event_info: %s\n", pfm_strerror(ret));
ret = 1;
goto end;
}
/*
* Now that the event is found, try to use it to validate that
* the current user has access to it and that it can be used on that
* host.
*/
/* Set the event to disabled to prevent unnecessary side effects. */
pencoder.attr->disabled = 1;
/* perf_event_open is provided by perfmon/perf_event.h. */
fd = perf_event_open(pencoder.attr, 0, -1, -1, 0);
if (fd == -1) {
fprintf(stderr, "perf: error perf_event_open: %d: %s\n", errno,
strerror(errno));
ret = 2;
goto end;
}
/* We close the fd immediately since the event is actionable. */
close(fd);
/* Output the raw code for the event */
fprintf(stdout, "r%" PRIx64 "\n", info.code);
ret = 0;
end:
return ret;
}
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