diff options
Diffstat (limited to 'lib/trace-cmd/trace-perf.c')
-rw-r--r-- | lib/trace-cmd/trace-perf.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/lib/trace-cmd/trace-perf.c b/lib/trace-cmd/trace-perf.c new file mode 100644 index 00000000..a10da55d --- /dev/null +++ b/lib/trace-cmd/trace-perf.c @@ -0,0 +1,105 @@ +// 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; +} |