Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755517AbbG1LSB (ORCPT ); Tue, 28 Jul 2015 07:18:01 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:1490 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755384AbbG1LR6 (ORCPT ); Tue, 28 Jul 2015 07:17:58 -0400 From: Kaixu Xia To: , , , , , , , CC: , , , , Subject: [PATCH v4 0/4] bpf: Introduce the new ability of eBPF programs to access hardware PMU counter Date: Tue, 28 Jul 2015 11:17:31 +0000 Message-ID: <1438082255-60683-1-git-send-email-xiakaixu@huawei.com> X-Mailer: git-send-email 1.8.3.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.193.250] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4047 Lines: 101 Previous patch v3 url: https://lkml.org/lkml/2015/7/23/203 changes in V4: - make the bpf_prog_array_map more generic; - fix the bug of event refcnt leak; - use more useful errno in bpf_perf_event_read(); changes in V3: - collapse V2 patches 1-3 into one; - drop the function map->ops->map_traverse_elem() and release the struct perf_event in map_free; - only allow to access bpf_perf_event_read() from programs; - update the perf_event_array_map elem via xchg(); - pass index directly to bpf_perf_event_read() instead of MAP_KEY; changes in V2: - put atomic_long_inc_not_zero() between fdget() and fdput(); - limit the event type to PERF_TYPE_RAW and PERF_TYPE_HARDWARE; - Only read the event counter on current CPU or on current process; - add new map type BPF_MAP_TYPE_PERF_EVENT_ARRAY to store the pointer to the struct perf_event; - according to the perf_event_map_fd and key, the function bpf_perf_event_read() can get the Hardware PMU counter value; Patch 4/4 is a simple example and shows how to use this new eBPF programs ability. The PMU counter data can be found in /sys/kernel/debug/tracing/trace(trace_pipe).(the cycles PMU value when 'kprobe/sys_write' sampling) $ cat /sys/kernel/debug/tracing/trace_pipe $ ./tracex6 ... syslog-ng-548 [000] d..1 76.905673: : CPU-0 681765271 syslog-ng-548 [000] d..1 76.905690: : CPU-0 681787855 syslog-ng-548 [000] d..1 76.905707: : CPU-0 681810504 syslog-ng-548 [000] d..1 76.905725: : CPU-0 681834771 syslog-ng-548 [000] d..1 76.905745: : CPU-0 681859519 syslog-ng-548 [000] d..1 76.905766: : CPU-0 681890419 syslog-ng-548 [000] d..1 76.905783: : CPU-0 681914045 syslog-ng-548 [000] d..1 76.905800: : CPU-0 681935950 syslog-ng-548 [000] d..1 76.905816: : CPU-0 681958299 ls-690 [005] d..1 82.241308: : CPU-5 3138451 sh-691 [004] d..1 82.244570: : CPU-4 7324988 <...>-699 [007] d..1 99.961387: : CPU-7 3194027 <...>-695 [003] d..1 99.961474: : CPU-3 288901 <...>-695 [003] d..1 99.961541: : CPU-3 383145 <...>-695 [003] d..1 99.961591: : CPU-3 450365 <...>-695 [003] d..1 99.961639: : CPU-3 515751 <...>-695 [003] d..1 99.961686: : CPU-3 579047 ... The detail of patches is as follow: Patch 1/4 rewrites part of the bpf_prog_array map code and make it more generic; Patch 2/4 introduces a new bpf map type. This map only stores the pointer to struct perf_event; Patch 3/4 implements function bpf_perf_event_read() that get the selected hardware PMU conuter; Patch 4/4 gives a simple example. Kaixu Xia (3): bpf: Add new bpf map type to store the pointer to struct perf_event bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter samples/bpf: example of get selected PMU counter value Wang Nan (1): bpf: Make the bpf_prog_array_map more generic include/linux/bpf.h | 8 ++- include/linux/perf_event.h | 5 +- include/uapi/linux/bpf.h | 2 + kernel/bpf/arraymap.c | 161 ++++++++++++++++++++++++++++++++++++--------- kernel/bpf/helpers.c | 36 ++++++++++ kernel/bpf/syscall.c | 4 +- kernel/bpf/verifier.c | 15 +++++ kernel/events/core.c | 21 +++++- kernel/trace/bpf_trace.c | 2 + samples/bpf/Makefile | 4 ++ samples/bpf/bpf_helpers.h | 2 + samples/bpf/tracex6_kern.c | 26 ++++++++ samples/bpf/tracex6_user.c | 67 +++++++++++++++++++ 13 files changed, 316 insertions(+), 37 deletions(-) create mode 100644 samples/bpf/tracex6_kern.c create mode 100644 samples/bpf/tracex6_user.c -- 1.8.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/