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// SPDX-License-Identifier: LGPL-2.1
/*
* Copyright (C) 2021, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
*
*/
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#include "trace-cmd-private.h"
static void default_perf_init_pe(struct perf_event_attr *pe)
{
pe->type = PERF_TYPE_SOFTWARE;
pe->sample_type = PERF_SAMPLE_CPU;
pe->size = sizeof(struct perf_event_attr);
pe->config = PERF_COUNT_HW_CPU_CYCLES;
pe->disabled = 1;
pe->exclude_kernel = 1;
pe->freq = 1;
pe->sample_freq = 1000;
pe->inherit = 1;
pe->mmap = 1;
pe->comm = 1;
pe->task = 1;
pe->precise_ip = 1;
pe->sample_id_all = 1;
pe->read_format = PERF_FORMAT_ID |
PERF_FORMAT_TOTAL_TIME_ENABLED |
PERF_FORMAT_TOTAL_TIME_RUNNING;
}
/**
* trace_perf_init - Initialize perf context
*
* @perf: structure, representing perf context, that will be initialized.
* @pages: Number of perf memory mapped pages.
* @cpu: CPU number, associated with this perf context.
* @pid: PID, associated with this perf context.
*
* The perf context in initialized with default values. The caller can set
* custom perf parameters in perf->pe, before calling trace_perf_open() API.
*
* Returns 0 on success, or -1 in case of an error.
*
*/
int __hidden trace_perf_init(struct trace_perf *perf, int pages, int cpu, int pid)
{
if (!perf)
return -1;
memset(perf, 0, sizeof(struct trace_perf));
default_perf_init_pe(&perf->pe);
perf->cpu = cpu;
perf->pages = pages;
perf->pid = pid;
perf->fd = -1;
return 0;
}
/**
* trace_perf_close - Close perf session
*
* @perf: structure, representing context of a running perf session, opened
* with trace_perf_open()
*
*/
void __hidden trace_perf_close(struct trace_perf *perf)
{
if (perf->fd >= 0)
close(perf->fd);
perf->fd = -1;
if (perf->mmap && perf->mmap != MAP_FAILED)
munmap(perf->mmap, (perf->pages + 1) * getpagesize());
perf->mmap = NULL;
}
/**
* trace_perf_open - Open perf session
*
* @perf: structure, representing perf context that will be opened. It must be
* initialized with trace_perf_init().
*
* Returns 0 on success, or -1 in case of an error. In case of success, the
* session must be closed with trace_perf_close()
*/
int __hidden trace_perf_open(struct trace_perf *perf)
{
perf->fd = syscall(__NR_perf_event_open, &perf->pe, perf->pid, perf->cpu, -1, 0);
if (perf->fd < 0)
return -1;
fcntl(perf->fd, F_SETFL, O_NONBLOCK);
perf->mmap = mmap(NULL, (perf->pages + 1) * getpagesize(),
PROT_READ | PROT_WRITE, MAP_SHARED, perf->fd, 0);
if (perf->mmap == MAP_FAILED)
goto error;
return 0;
error:
trace_perf_close(perf);
return -1;
}
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