From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E6B28288CB3 for ; Tue, 3 Jun 2025 18:16:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748974614; cv=none; b=G+7pZiXtlZiLVIcB4FxFSZdwU2gOwTXhECzRaBVg9+hc2oJYFYOaT7Br75bSHzbTzRbtFetXdHaQC/iLCgdLaj+B+z/86kuT+T01V7CFCV9fUK/UClILoDToaVnmV7awWpTTWEy7tl1WTlKxyE0qk4scbAXXDJ0uLwqAQJrq2l0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748974614; c=relaxed/simple; bh=wBMwFZ65rrg8ho4R1itK1EGQahIG96i90ewd1ea9HYg=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=icjbYkiUqbKBU5b5zR9BRY8QqIM9FOeWLjuKXxetXn4+ZVCuPreSk9MnDMylv/+Ogfd3zCli4g1Y/QshKYE231XCjKxc/aGBQvBDs260HWLLG3VlsBmBzIqCLTyEGiDPgZETDin7akNmNtSWjATgpOYvKMGBuNyDDp7jcj5YOL8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--ctshao.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=FtvKk2i7; arc=none smtp.client-ip=209.85.210.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--ctshao.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FtvKk2i7" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-7394772635dso3940184b3a.0 for ; Tue, 03 Jun 2025 11:16:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1748974612; x=1749579412; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=XvHfZvteDDVqcCnEge2jWEzX4DjmZnrKZWBqnzvh3sM=; b=FtvKk2i7DM7s4ZJvbtTccyj9kDRt5eJoEBNDFXUWW9GEP8doLWIVIgvoFmIJPpCEEV xe/hSdd2qZhh+FK3/8zj9JddLw8fEqaDwawppFcwrb4ZIMkEH1WtNGJSuKfg/hnEiSy1 zOk0/zVEBjmCzJCyjRiv/6JIsaFxIwSlugA2WqEgjqAXD2IKZlFrbWqvJyoFC+J03O/W hkADPPrM6q4leOkfUcx4/ETS0Kr94eXQi1vuHehWvdl0xDwRJtfXVfxvhcW/MMCfDBpJ Ohj3RCV/0pl1VKycUaolJIi5Z9Oi+azEYLwrjydQsmOO1/7AAzWCbGCXElI7a+EvqYw9 Jrpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1748974612; x=1749579412; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=XvHfZvteDDVqcCnEge2jWEzX4DjmZnrKZWBqnzvh3sM=; b=tmqWkr2dRMtwgZh5wAhM5q+JXnRxQOXzrCwZgL91bK9gd8YywTw3vu0oXRQlAdY3tL zG1BeVWmrYZTR8Ym/nPGla25tQ2CBa4iBN6UxbPvekSiNtnZno/fjk592A1muZOp9q4f jxiD2j2+LldugFDf6XfNc8iMmok+LT6gZMSopzj0hyfnzBQKXwecGrw1yUo6F9DO4Cy9 OLQT7DWegJGsC5vzCzHL1dQE7DKA1UF9iUBYEM8/N91x0shL1LAHF5+PdIJGPlo+r8Gj eiJrxLCVdz6v0CdOj/5Ud2wB3d2vEOihN3or7FemCJGz7apJ59AStG2dep1cDO//Zyaa FTgg== X-Gm-Message-State: AOJu0YyX7nQNYZIpT6bBbyVtytZHE9TjoN+c7mb0Ml418F0j9tiLUMSS /TVk2h55Gf7uUrTD0aWouMazKX5c7hLe3rGFFUz2TU/z+e/fuQ3zNgKn4GsxIGIOmkBwJI+NJWJ XA4rhIaP5/MjSLqMB4/BY519LGMStYKh8jyAhVUlzDmCwlSSu/0ZQMtFYYPANvHqLC00atSYCqM 2lgE3w1M+rR63CQaYevZm/lcHRgm0EyCNwpT/EWXsk6oZa X-Google-Smtp-Source: AGHT+IEuYjk9n2uExO2tYukINHmxBE9zmSFBuDwroUnzVDGF4KT2eakPJ9ADydhQfQMyjArCbTyiOhGBzlU= X-Received: from pgbdh4.prod.google.com ([2002:a05:6a02:b84:b0:b2e:ce0c:b3fb]) (user=ctshao job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:3944:b0:1f5:8622:5ecb with SMTP id adf61e73a8af0-21ae00c7013mr33177374637.34.1748974612100; Tue, 03 Jun 2025 11:16:52 -0700 (PDT) Date: Tue, 3 Jun 2025 11:15:54 -0700 In-Reply-To: <20250603181634.1362626-1-ctshao@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250603181634.1362626-1-ctshao@google.com> X-Mailer: git-send-email 2.49.0.1204.g71687c7c1d-goog Message-ID: <20250603181634.1362626-2-ctshao@google.com> Subject: [PATCH v4 2/2] perf evsel: Find process with busy PMUs for EBUSY From: Chun-Tse Shao To: linux-kernel@vger.kernel.org Cc: Chun-Tse Shao , Ian Rogers , peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, adrian.hunter@intel.com, kan.liang@linux.intel.com, james.clark@linaro.org, howardchu95@gmail.com, weilin.wang@intel.com, linux-perf-users@vger.kernel.org Content-Type: text/plain; charset="UTF-8" It parses fdinfo with PMU type, comparing with the event which failed to open, and report the processes causing EBUSY error. Testing cycles and intel_pt// $ ./perf stat -e cycles & [1] 55569 $ ./perf stat -e intel_pt// & [2] 55683 $ ./perf stat -e intel_pt// Error: The PMU intel_pt counters are busy and in use by another process. Possible processes: 55683 ./perf stat -e intel_pt// Only perf with intel_pt was reported. Reviewed-by: Ian Rogers Signed-off-by: Chun-Tse Shao --- v4: Removed the first patch in v3 since it is merged. Retested to make sure the patch still work. v3: lore.kernel.org/20241106003007.2112584-3-ctshao@google.com/ tools/perf/util/evsel.c | 79 +++++++++++++++++++++++++++++------------ 1 file changed, 57 insertions(+), 22 deletions(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index d55482f094bf..fa281ea15a25 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -3619,7 +3619,8 @@ static bool find_process(const char *name) return ret ? false : true; } -static int dump_perf_event_processes(char *msg, size_t size) +static int dump_perf_event_processes(const struct perf_event_attr *failed_attr, + char *msg, size_t size) { DIR *proc_dir; struct dirent *proc_entry; @@ -3660,29 +3661,61 @@ static int dump_perf_event_processes(char *msg, size_t size) continue; /* Take care as readlink doesn't null terminate the string. */ if (!strncmp(buf, "anon_inode:[perf_event]", link_size)) { - int cmdline_fd; - ssize_t cmdline_size; - - scnprintf(buf, sizeof(buf), "%s/cmdline", proc_entry->d_name); - cmdline_fd = openat(dirfd(proc_dir), buf, O_RDONLY); - if (cmdline_fd == -1) - continue; - cmdline_size = read(cmdline_fd, buf, sizeof(buf) - 1); - close(cmdline_fd); - if (cmdline_size < 0) + int fdinfo_fd; + ssize_t fdinfo_size; + char *line; + u32 perf_event_type = UINT32_MAX; + + /* Let's check the PMU type reserved by this process */ + scnprintf(buf, sizeof(buf), "%s/fdinfo/%s", + proc_entry->d_name, fd_entry->d_name); + fdinfo_fd = openat(dirfd(proc_dir), buf, O_RDONLY); + fdinfo_size = read(fdinfo_fd, buf, sizeof(buf) - 1); + if (fdinfo_size < 0) continue; - buf[cmdline_size] = '\0'; - for (ssize_t i = 0; i < cmdline_size; i++) { - if (buf[i] == '\0') - buf[i] = ' '; + buf[fdinfo_size] = '\0'; + + line = strtok(buf, "\n"); + while (line != NULL) { + if (sscanf(line, + "perf_event_attr.type:\t%u", + &perf_event_type) == 1) + break; + line = strtok(NULL, "\n"); } - if (printed == 0) - printed += scnprintf(msg, size, "Possible processes:\n"); - - printed += scnprintf(msg + printed, size - printed, - "%s %s\n", proc_entry->d_name, buf); - break; + /* Report the process which reserves the conflicted PMU. */ + /* If fdinfo does not contain PMU type, report it too. */ + if (perf_event_type == failed_attr->type || + perf_event_type == UINT32_MAX) { + int cmdline_fd; + ssize_t cmdline_size; + + scnprintf(buf, sizeof(buf), + "%s/cmdline", + proc_entry->d_name); + cmdline_fd = openat(dirfd(proc_dir), buf, O_RDONLY); + if (cmdline_fd == -1) + continue; + cmdline_size = read(cmdline_fd, buf, sizeof(buf) - 1); + close(cmdline_fd); + if (cmdline_size < 0) + continue; + buf[cmdline_size] = '\0'; + for (ssize_t i = 0; i < cmdline_size; i++) { + if (buf[i] == '\0') + buf[i] = ' '; + } + + if (printed == 0) + printed += scnprintf( + msg, size, + "Possible processes:\n"); + + printed += scnprintf(msg + printed, size - printed, + "%s %s\n", proc_entry->d_name, buf); + break; + } } } closedir(fd_dir); @@ -3799,7 +3832,9 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target, msg, size, "The PMU %s counters are busy and in use by another process.\n", evsel->pmu ? evsel->pmu->name : ""); - return printed + dump_perf_event_processes(msg + printed, size - printed); + return printed + dump_perf_event_processes(&evsel->core.attr, + msg + printed, + size - printed); break; case EINVAL: if (evsel->core.attr.sample_type & PERF_SAMPLE_CODE_PAGE_SIZE && perf_missing_features.code_page_size) -- 2.49.0.1204.g71687c7c1d-goog