From patchwork Sun Feb 19 06:13:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13145790 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4A7DDC6379F for ; Sun, 19 Feb 2023 06:13:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229472AbjBSGNg (ORCPT ); Sun, 19 Feb 2023 01:13:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229451AbjBSGNf (ORCPT ); Sun, 19 Feb 2023 01:13:35 -0500 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0FA41284F; Sat, 18 Feb 2023 22:13:33 -0800 (PST) Received: by mail-pj1-x1034.google.com with SMTP id f8-20020a17090ac28800b00233d7314c1cso103548pjt.5; Sat, 18 Feb 2023 22:13:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:sender:from:to:cc:subject:date:message-id:reply-to; bh=CFrwnNzp2n5WpLXHuNKvDPK4cjyVcEK2vzsBOgk9tkg=; b=DpGxweCwdGeEkBFtQnkBpactcZ+ROSu5QTQdKlBVN4shK8zjInCgCwWI3KQZIspYfq /7TtI49x5O7DDwOIroL0BZlUt/EN+3vTRsmFN6gEG/aynx/ZvkwwGICvsegpqKYE5PLp qboUubRGQK17MDqTlLEDgyySwHaCNaBW4ssu+Se50LyICD4fFT7ZN+J/L7ZBtVZe7do5 Daum7BmA0INjIdGN1SSEb1PnLNblcYldj8yrX2oerpFBM/3QVnBGISZLTn1A8HOLQY/F WRK8yofuPedzU0kIImwWgo2cx4DaEyY5K14ABQJ6iiaC2XGVhkALCJbFdkuHGndlRhvs BU1Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:sender:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=CFrwnNzp2n5WpLXHuNKvDPK4cjyVcEK2vzsBOgk9tkg=; b=4MZC4b+zD5AnWleKRtSKNXv6M+Wz5l8PdGYkyrh20QlYa1nhnaeEeld0aplQJfuud6 UqElXRVUDCBWoquSAJJCFl2lpoPZW1NKwfZoxniEP8ohhzmEfeP54+6nuZW6UWOeMG2b ucVt5g9S/vQR+MicxdkpD/HIFW3nvZclD7Ys3RYVykIQjYF29V5kiP+oe3jSeyUm9mVn G8idAj3LKVeXvy5lCRG29fR+Lpqw1HJdG8/WnsdpqKObfW9rxy6u8m/WZGusRlrTOjDr fQ6tTkV+TGs3zwBcqkhy5VoBD83YTofc40/L+jNi7d6WuJpDLG5KqFrGzdu4c5NXc1qk 87iA== X-Gm-Message-State: AO0yUKUOhP5rc/g4d6QobIzrA2uAFtl7BHiMBuVlBVeThz4GPvw1Te30 66kZizKk7fcqTMXcIvPa6OA= X-Google-Smtp-Source: AK7set9fls6FjYvyR3/WMQglUDJr/Ahvl3SOcQ1PJMG3eLnngqd/owr45dzpfaySm/UumUvCPUJvHA== X-Received: by 2002:a05:6a21:33a7:b0:bc:e785:5ad3 with SMTP id yy39-20020a056a2133a700b000bce7855ad3mr6823681pzb.29.1676787213063; Sat, 18 Feb 2023 22:13:33 -0800 (PST) Received: from moohyul.svl.corp.google.com ([2620:15c:2d4:203:70ac:ab5:11d3:d785]) by smtp.gmail.com with ESMTPSA id q16-20020a170902dad000b00189ac5a2340sm1182140plx.124.2023.02.18.22.13.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 18 Feb 2023 22:13:32 -0800 (PST) Sender: Namhyung Kim From: Namhyung Kim To: Arnaldo Carvalho de Melo , Jiri Olsa Cc: Peter Zijlstra , Ingo Molnar , Ian Rogers , Adrian Hunter , Andi Kleen , Kan Liang , Song Liu , Stephane Eranian , Ravi Bangoria , Leo Yan , James Clark , Hao Luo , LKML , linux-perf-users@vger.kernel.org, bpf@vger.kernel.org Subject: [RFC/PATCHSET 0/8] perf record: Implement BPF sample filter (v2) Date: Sat, 18 Feb 2023 22:13:21 -0800 Message-Id: <20230219061329.1001079-1-namhyung@kernel.org> X-Mailer: git-send-email 2.39.2.637.g21b0678d19-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-State: RFC Hello, There have been requests for more sophisticated perf event sample filtering based on the sample data. Recently the kernel added BPF programs can access perf sample data and this is the userspace part to enable such a filtering. This still has some rough edges and needs more improvements. But I'd like to share the current work and get some feedback for the directions and idea for further improvements. v2 changes) * fix build error with the misc field (Jiri) * add a destructor for filter expr (Ian) * remove 'bpf:' prefix (Arnaldo) * add '||' operator The kernel changes are in the tip.git tree (perf/core branch) for now. perf record has --filter option to set filters on the last specified event in the command line. It worked only for tracepoints and Intel PT events so far. This patchset extends it to have 'bpf:' prefix in order to enable the general sample filters using BPF for any events. A new filter expression parser was added (using flex/bison) to process the filter string. Right now, it only accepts very simple expressions separated by comma. I'd like to keep the filter expression as simple as possible. It requires samples satisfy all the filter expressions otherwise it'd drop the sample. IOW filter expressions are connected with logical AND operations implicitly. Essentially the BPF filter expression is: (("," | "||") )* The can be one of: ip, id, tid, pid, cpu, time, addr, period, txn, weight, phys_addr, code_pgsz, data_pgsz, weight1, weight2, weight3, ins_lat, retire_lat, p_stage_cyc, mem_op, mem_lvl, mem_snoop, mem_remote, mem_lock, mem_dtlb, mem_blk, mem_hops The can be one of: ==, !=, >, >=, <, <=, & The can be one of: (for any term) na, load, store, pfetch, exec (for mem_op) l1, l2, l3, l4, cxl, io, any_cache, lfb, ram, pmem (for mem_lvl) na, none, hit, miss, hitm, fwd, peer (for mem_snoop) remote (for mem_remote) na, locked (for mem_locked) na, l1_hit, l1_miss, l2_hit, l2_miss, any_hit, any_miss, walk, fault (for mem_dtlb) na, by_data, by_addr (for mem_blk) hops0, hops1, hops2, hops3 (for mem_hops) I plan to improve it with range expressions like for ip or addr and it should support symbols like the existing addr-filters. Also cgroup should understand and convert cgroup names to IDs. Let's take a look at some examples. The following is to profile a user program on the command line. When the frequency mode is used, it starts with a very small period (i.e. 1) and adjust it on every interrupt (NMI) to catch up the given frequency. $ ./perf record -- ./perf test -w noploop [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.263 MB perf.data (4006 samples) ] $ ./perf script -F pid,period,event,ip,sym | head 36695 1 cycles: ffffffffbab12ddd perf_event_exec 36695 1 cycles: ffffffffbab12ddd perf_event_exec 36695 5 cycles: ffffffffbab12ddd perf_event_exec 36695 46 cycles: ffffffffbab12de5 perf_event_exec 36695 1163 cycles: ffffffffba80a0eb x86_pmu_disable_all 36695 1304 cycles: ffffffffbaa19507 __hrtimer_get_next_event 36695 8143 cycles: ffffffffbaa186f9 __run_timers 36695 69040 cycles: ffffffffbaa0c393 rcu_segcblist_ready_cbs 36695 355117 cycles: 4b0da4 noploop 36695 321861 cycles: 4b0da4 noploop If you want to skip the first few samples that have small periods, you can do like this (note it requires root due to BPF). $ sudo ./perf record -e cycles --filter 'period > 10000' -- ./perf test -w noploop [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.262 MB perf.data (3990 samples) ] $ sudo ./perf script -F pid,period,event,ip,sym | head 39524 58253 cycles: ffffffffba97dac0 update_rq_clock 39524 232657 cycles: 4b0da2 noploop 39524 210981 cycles: 4b0da2 noploop 39524 282882 cycles: 4b0da4 noploop 39524 392180 cycles: 4b0da4 noploop 39524 456058 cycles: 4b0da4 noploop 39524 415196 cycles: 4b0da2 noploop 39524 462721 cycles: 4b0da4 noploop 39524 526272 cycles: 4b0da2 noploop 39524 565569 cycles: 4b0da4 noploop Maybe more useful example is when it deals with precise memory events. On AMD processors with IBS, you can filter only memory load with L1 dTLB is missed like below. $ sudo ./perf record -ad -e ibs_op//p \ > --filter 'mem_op == load, mem_dtlb > l1_hit' sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 1.338 MB perf.data (15 samples) ] $ sudo ./perf script -F data_src | head 51080242 |OP LOAD|LVL LFB/MAB hit|SNP N/A|TLB L2 miss|LCK N/A|BLK N/A 49080142 |OP LOAD|LVL L1 hit|SNP N/A|TLB L2 hit|LCK N/A|BLK N/A 51080242 |OP LOAD|LVL LFB/MAB hit|SNP N/A|TLB L2 miss|LCK N/A|BLK N/A 51080242 |OP LOAD|LVL LFB/MAB hit|SNP N/A|TLB L2 miss|LCK N/A|BLK N/A 51088842 |OP LOAD|LVL L3 or Remote Cache (1 hop) hit|SNP N/A|TLB L2 miss|LCK N/A|BLK N/A 51080242 |OP LOAD|LVL LFB/MAB hit|SNP N/A|TLB L2 miss|LCK N/A|BLK N/A 51080242 |OP LOAD|LVL LFB/MAB hit|SNP N/A|TLB L2 miss|LCK N/A|BLK N/A 51080242 |OP LOAD|LVL LFB/MAB hit|SNP N/A|TLB L2 miss|LCK N/A|BLK N/A 49080442 |OP LOAD|LVL L2 hit|SNP N/A|TLB L2 hit|LCK N/A|BLK N/A 51080242 |OP LOAD|LVL LFB/MAB hit|SNP N/A|TLB L2 miss|LCK N/A|BLK N/A You can also check the number of dropped samples in LOST_SAMPLES events using perf report --stat command. $ sudo ./perf report --stat Aggregated stats: TOTAL events: 16066 MMAP events: 22 ( 0.1%) COMM events: 4166 (25.9%) EXIT events: 1 ( 0.0%) THROTTLE events: 816 ( 5.1%) UNTHROTTLE events: 613 ( 3.8%) FORK events: 4165 (25.9%) SAMPLE events: 15 ( 0.1%) MMAP2 events: 6133 (38.2%) LOST_SAMPLES events: 1 ( 0.0%) KSYMBOL events: 69 ( 0.4%) BPF_EVENT events: 57 ( 0.4%) FINISHED_ROUND events: 3 ( 0.0%) ID_INDEX events: 1 ( 0.0%) THREAD_MAP events: 1 ( 0.0%) CPU_MAP events: 1 ( 0.0%) TIME_CONV events: 1 ( 0.0%) FINISHED_INIT events: 1 ( 0.0%) ibs_op//p stats: SAMPLE events: 15 LOST_SAMPLES events: 3991 Note that the total aggregated stats show 1 LOST_SAMPLES event but per event stats show 3991 events because it's the actual number of dropped samples while the aggregated stats has the number of record. Maybe we need to change the per-event stats to 'LOST_SAMPLES count' to avoid the confusion. The code is available at 'perf/bpf-filter-v2' branch in my tree. git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git Again, you need tip/perf/core kernel for this to work. Any feedback is welcome. Thanks, Namhyung Namhyung Kim (8): perf bpf filter: Introduce basic BPF filter expression perf bpf filter: Implement event sample filtering perf record: Add BPF event filter support perf record: Record dropped sample count perf bpf filter: Add 'pid' sample data support perf bpf filter: Add more weight sample data support perf bpf filter: Add data_src sample data support perf bpf filter: Add logical OR operator tools/lib/perf/include/perf/event.h | 2 + tools/perf/Documentation/perf-record.txt | 15 +- tools/perf/Makefile.perf | 2 +- tools/perf/builtin-record.c | 46 ++++-- tools/perf/util/Build | 16 ++ tools/perf/util/bpf-filter.c | 142 ++++++++++++++++ tools/perf/util/bpf-filter.h | 49 ++++++ tools/perf/util/bpf-filter.l | 147 +++++++++++++++++ tools/perf/util/bpf-filter.y | 77 +++++++++ tools/perf/util/bpf_counter.c | 3 +- tools/perf/util/bpf_skel/sample-filter.h | 27 +++ tools/perf/util/bpf_skel/sample_filter.bpf.c | 164 +++++++++++++++++++ tools/perf/util/evsel.c | 2 + tools/perf/util/evsel.h | 7 +- tools/perf/util/parse-events.c | 8 +- tools/perf/util/session.c | 3 +- 16 files changed, 682 insertions(+), 28 deletions(-) create mode 100644 tools/perf/util/bpf-filter.c create mode 100644 tools/perf/util/bpf-filter.h create mode 100644 tools/perf/util/bpf-filter.l create mode 100644 tools/perf/util/bpf-filter.y create mode 100644 tools/perf/util/bpf_skel/sample-filter.h create mode 100644 tools/perf/util/bpf_skel/sample_filter.bpf.c base-commit: f9fa0778ee7349a9aa3d2ea10e9f2ab843a0b44e