perf evlist: Add support for mmapping an AUX area buffer
This patch supports the addition to the kernel of AUX area buffers that can be mmapped separately from the perf-events buffer. The AUX buffer can be configured to contain hardware-produced trace information. The first implementation will support Intel BTS and Intel PT. One auxtrace buffer is mmapped per perf-events buffer. If the requested auxtrace buffer size is zero, which it will be until further support is added, then no auxtrace mmapping is attempted. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1428594864-29309-3-git-send-email-adrian.hunter@intel.com [ Fixed conflict in evlist.h ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter
Arnaldo Carvalho de Melo
Родитель
4025ea4024
Коммит
718c602d67
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@ -74,6 +74,7 @@ libperf-y += data.o
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libperf-$(CONFIG_X86) += tsc.o
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libperf-y += cloexec.o
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libperf-y += thread-stack.o
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libperf-y += auxtrace.o
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libperf-$(CONFIG_LIBELF) += symbol-elf.o
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libperf-$(CONFIG_LIBELF) += probe-event.o
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@ -0,0 +1,113 @@
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/*
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* auxtrace.c: AUX area trace support
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* Copyright (c) 2013-2015, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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*/
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <stdbool.h>
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#include <linux/kernel.h>
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#include <linux/perf_event.h>
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#include <linux/types.h>
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#include <linux/bitops.h>
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#include <linux/log2.h>
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#include "../perf.h"
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#include "util.h"
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#include "evlist.h"
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#include "cpumap.h"
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#include "thread_map.h"
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#include "asm/bug.h"
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#include "auxtrace.h"
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int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
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struct auxtrace_mmap_params *mp,
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void *userpg, int fd)
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{
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struct perf_event_mmap_page *pc = userpg;
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#if BITS_PER_LONG != 64 && !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
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pr_err("Cannot use AUX area tracing mmaps\n");
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return -1;
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#endif
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WARN_ONCE(mm->base, "Uninitialized auxtrace_mmap\n");
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mm->userpg = userpg;
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mm->mask = mp->mask;
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mm->len = mp->len;
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mm->prev = 0;
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mm->idx = mp->idx;
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mm->tid = mp->tid;
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mm->cpu = mp->cpu;
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if (!mp->len) {
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mm->base = NULL;
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return 0;
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}
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pc->aux_offset = mp->offset;
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pc->aux_size = mp->len;
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mm->base = mmap(NULL, mp->len, mp->prot, MAP_SHARED, fd, mp->offset);
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if (mm->base == MAP_FAILED) {
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pr_debug2("failed to mmap AUX area\n");
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mm->base = NULL;
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return -1;
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}
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return 0;
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}
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void auxtrace_mmap__munmap(struct auxtrace_mmap *mm)
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{
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if (mm->base) {
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munmap(mm->base, mm->len);
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mm->base = NULL;
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}
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}
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void auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp,
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off_t auxtrace_offset,
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unsigned int auxtrace_pages,
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bool auxtrace_overwrite)
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{
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if (auxtrace_pages) {
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mp->offset = auxtrace_offset;
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mp->len = auxtrace_pages * (size_t)page_size;
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mp->mask = is_power_of_2(mp->len) ? mp->len - 1 : 0;
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mp->prot = PROT_READ | (auxtrace_overwrite ? 0 : PROT_WRITE);
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pr_debug2("AUX area mmap length %zu\n", mp->len);
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} else {
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mp->len = 0;
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}
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}
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void auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp,
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struct perf_evlist *evlist, int idx,
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bool per_cpu)
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{
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mp->idx = idx;
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if (per_cpu) {
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mp->cpu = evlist->cpus->map[idx];
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if (evlist->threads)
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mp->tid = evlist->threads->map[0];
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else
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mp->tid = -1;
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} else {
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mp->cpu = -1;
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mp->tid = evlist->threads->map[idx];
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}
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}
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@ -0,0 +1,117 @@
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/*
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* auxtrace.h: AUX area trace support
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* Copyright (c) 2013-2015, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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*/
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#ifndef __PERF_AUXTRACE_H
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#define __PERF_AUXTRACE_H
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#include <sys/types.h>
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#include <stdbool.h>
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#include <linux/perf_event.h>
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#include <linux/types.h>
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#include "../perf.h"
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struct perf_evlist;
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/**
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* struct auxtrace_mmap - records an mmap of the auxtrace buffer.
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* @base: address of mapped area
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* @userpg: pointer to buffer's perf_event_mmap_page
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* @mask: %0 if @len is not a power of two, otherwise (@len - %1)
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* @len: size of mapped area
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* @prev: previous aux_head
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* @idx: index of this mmap
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* @tid: tid for a per-thread mmap (also set if there is only 1 tid on a per-cpu
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* mmap) otherwise %0
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* @cpu: cpu number for a per-cpu mmap otherwise %-1
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*/
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struct auxtrace_mmap {
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void *base;
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void *userpg;
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size_t mask;
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size_t len;
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u64 prev;
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int idx;
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pid_t tid;
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int cpu;
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};
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/**
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* struct auxtrace_mmap_params - parameters to set up struct auxtrace_mmap.
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* @mask: %0 if @len is not a power of two, otherwise (@len - %1)
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* @offset: file offset of mapped area
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* @len: size of mapped area
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* @prot: mmap memory protection
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* @idx: index of this mmap
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* @tid: tid for a per-thread mmap (also set if there is only 1 tid on a per-cpu
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* mmap) otherwise %0
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* @cpu: cpu number for a per-cpu mmap otherwise %-1
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*/
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struct auxtrace_mmap_params {
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size_t mask;
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off_t offset;
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size_t len;
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int prot;
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int idx;
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pid_t tid;
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int cpu;
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};
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static inline u64 auxtrace_mmap__read_head(struct auxtrace_mmap *mm)
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{
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struct perf_event_mmap_page *pc = mm->userpg;
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#if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
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u64 head = ACCESS_ONCE(pc->aux_head);
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#else
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u64 head = __sync_val_compare_and_swap(&pc->aux_head, 0, 0);
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#endif
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/* Ensure all reads are done after we read the head */
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rmb();
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return head;
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}
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static inline void auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail)
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{
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struct perf_event_mmap_page *pc = mm->userpg;
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#if BITS_PER_LONG != 64 && defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
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u64 old_tail;
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#endif
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/* Ensure all reads are done before we write the tail out */
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mb();
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#if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
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pc->aux_tail = tail;
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#else
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do {
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old_tail = __sync_val_compare_and_swap(&pc->aux_tail, 0, 0);
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} while (!__sync_bool_compare_and_swap(&pc->aux_tail, old_tail, tail));
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#endif
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}
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int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
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struct auxtrace_mmap_params *mp,
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void *userpg, int fd);
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void auxtrace_mmap__munmap(struct auxtrace_mmap *mm);
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void auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp,
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off_t auxtrace_offset,
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unsigned int auxtrace_pages,
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bool auxtrace_overwrite);
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void auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp,
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struct perf_evlist *evlist, int idx,
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bool per_cpu);
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#endif
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@ -725,6 +725,34 @@ void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx)
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perf_evlist__mmap_put(evlist, idx);
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}
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int __weak auxtrace_mmap__mmap(struct auxtrace_mmap *mm __maybe_unused,
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struct auxtrace_mmap_params *mp __maybe_unused,
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void *userpg __maybe_unused,
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int fd __maybe_unused)
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{
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return 0;
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}
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void __weak auxtrace_mmap__munmap(struct auxtrace_mmap *mm __maybe_unused)
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{
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}
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void __weak auxtrace_mmap_params__init(
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struct auxtrace_mmap_params *mp __maybe_unused,
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off_t auxtrace_offset __maybe_unused,
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unsigned int auxtrace_pages __maybe_unused,
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bool auxtrace_overwrite __maybe_unused)
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{
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}
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void __weak auxtrace_mmap_params__set_idx(
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struct auxtrace_mmap_params *mp __maybe_unused,
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struct perf_evlist *evlist __maybe_unused,
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int idx __maybe_unused,
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bool per_cpu __maybe_unused)
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{
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}
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static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx)
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{
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if (evlist->mmap[idx].base != NULL) {
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@ -732,6 +760,7 @@ static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx)
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evlist->mmap[idx].base = NULL;
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evlist->mmap[idx].refcnt = 0;
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}
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auxtrace_mmap__munmap(&evlist->mmap[idx].auxtrace_mmap);
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}
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void perf_evlist__munmap(struct perf_evlist *evlist)
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@ -759,6 +788,7 @@ static int perf_evlist__alloc_mmap(struct perf_evlist *evlist)
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struct mmap_params {
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int prot;
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int mask;
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struct auxtrace_mmap_params auxtrace_mp;
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};
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static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
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@ -789,6 +819,10 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
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return -1;
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}
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if (auxtrace_mmap__mmap(&evlist->mmap[idx].auxtrace_mmap,
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&mp->auxtrace_mp, evlist->mmap[idx].base, fd))
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return -1;
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return 0;
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}
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@ -853,6 +887,9 @@ static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist,
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for (cpu = 0; cpu < nr_cpus; cpu++) {
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int output = -1;
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auxtrace_mmap_params__set_idx(&mp->auxtrace_mp, evlist, cpu,
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true);
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for (thread = 0; thread < nr_threads; thread++) {
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if (perf_evlist__mmap_per_evsel(evlist, cpu, mp, cpu,
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thread, &output))
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@ -878,6 +915,9 @@ static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist,
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for (thread = 0; thread < nr_threads; thread++) {
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int output = -1;
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auxtrace_mmap_params__set_idx(&mp->auxtrace_mp, evlist, thread,
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false);
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if (perf_evlist__mmap_per_evsel(evlist, thread, mp, 0, thread,
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&output))
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goto out_unmap;
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@ -981,19 +1021,25 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
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}
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/**
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* perf_evlist__mmap - Create mmaps to receive events.
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* perf_evlist__mmap_ex - Create mmaps to receive events.
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* @evlist: list of events
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* @pages: map length in pages
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* @overwrite: overwrite older events?
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* @auxtrace_pages - auxtrace map length in pages
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* @auxtrace_overwrite - overwrite older auxtrace data?
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*
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* If @overwrite is %false the user needs to signal event consumption using
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* perf_mmap__write_tail(). Using perf_evlist__mmap_read() does this
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* automatically.
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*
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* Similarly, if @auxtrace_overwrite is %false the user needs to signal data
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* consumption using auxtrace_mmap__write_tail().
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*
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* Return: %0 on success, negative error code otherwise.
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*/
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int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
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bool overwrite)
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int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
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bool overwrite, unsigned int auxtrace_pages,
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bool auxtrace_overwrite)
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{
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struct perf_evsel *evsel;
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const struct cpu_map *cpus = evlist->cpus;
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@ -1013,6 +1059,9 @@ int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
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pr_debug("mmap size %zuB\n", evlist->mmap_len);
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mp.mask = evlist->mmap_len - page_size - 1;
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auxtrace_mmap_params__init(&mp.auxtrace_mp, evlist->mmap_len,
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auxtrace_pages, auxtrace_overwrite);
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evlist__for_each(evlist, evsel) {
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if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
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evsel->sample_id == NULL &&
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@ -1026,6 +1075,12 @@ int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
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return perf_evlist__mmap_per_cpu(evlist, &mp);
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}
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int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
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bool overwrite)
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{
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return perf_evlist__mmap_ex(evlist, pages, overwrite, 0, false);
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}
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int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)
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{
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evlist->threads = thread_map__new_str(target->pid, target->tid,
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@ -8,6 +8,7 @@
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#include "event.h"
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#include "evsel.h"
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#include "util.h"
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#include "auxtrace.h"
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#include <unistd.h>
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struct pollfd;
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@ -28,6 +29,7 @@ struct perf_mmap {
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int mask;
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int refcnt;
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u64 prev;
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struct auxtrace_mmap auxtrace_mmap;
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char event_copy[PERF_SAMPLE_MAX_SIZE] __attribute__((aligned(8)));
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};
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@ -126,6 +128,9 @@ int perf_evlist__parse_mmap_pages(const struct option *opt,
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const char *str,
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int unset);
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int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
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bool overwrite, unsigned int auxtrace_pages,
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bool auxtrace_overwrite);
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int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
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bool overwrite);
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void perf_evlist__munmap(struct perf_evlist *evlist);
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