From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dy1-f201.google.com (mail-dy1-f201.google.com [74.125.82.201]) (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 895952FD7D3 for ; Mon, 18 May 2026 22:49:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779144548; cv=none; b=X/HFDw6IpgeWHwYWyUMyIRzrKNSlZEkkx1vZkG9P1i9P92KSEkgBE4SzQIsES9m9G1N4tseY2yCsKP8TmdQNTx8yUIDaBd1SH9jcObYDGSJDnV6iz/XrYLtgXwlT4H03Eq2oxI3SOghXqjVRDguT58Kj63KmJWd+IDwT0wJiyyA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779144548; c=relaxed/simple; bh=ojqdFjfpOzgKZ/9nJ4wDUjptQFaL04I9xwgufbxsvO4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=FtUmkG3txFXEg2E4aCIz8m3Tu8Wos2o9LiDISaccOtnDY85M2UchrLw/koWcDdSXIjmCoAqeV3IIFhE9ynAmSnZlsjt4gibCH7ZEMwWCh+X8dDE3gl3NUGXLNmkt93HgRHmL7BxJ+FydfnHFHj8en4/GUNpPun5LVHvhgHEw5YM= 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=b4ICnn3a; arc=none smtp.client-ip=74.125.82.201 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="b4ICnn3a" Received: by mail-dy1-f201.google.com with SMTP id 5a478bee46e88-2c16233ee11so4015868eec.1 for ; Mon, 18 May 2026 15:49:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779144546; x=1779749346; 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=4mXObPWxU093Hrs6Zz/xsS5eb+P0/Hk3FQjwiJUB5pM=; b=b4ICnn3axxeN6U/GYQQKQGYj1llovtabr7Q6IK2ucgUa2oJNahzn+baYaJlPt85EFn 8egQbISA/WLIN6laMQbJEmrA8DqvkVJh6fIY5LR306WXENts3Cbs8Glea5htdG/I0hFj L/IBUt5hxG4bjfQ78Jy5OmKjfcRF2pgVWpaTVaTnyLuF+iEDFT2yCjV5kQq+mrfwgUIS rwZRz8GdSODvFJrtJomv0mgOssgzF9SPrGhjKsWW6VYXrMq69g/vLEcPAs+4CHcuDj3c Y7UVLoUEFOH1WbfFuqkmMSSaM1XT4HUpfiOyNqjrA+VUUvG/zOXim0ZvGCl9nsYrlvia 7v9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779144546; x=1779749346; 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=4mXObPWxU093Hrs6Zz/xsS5eb+P0/Hk3FQjwiJUB5pM=; b=gqruYjHngM5rd/o32qJfPhtaknOZEfqhuB2CsxgXd5gDImwU5sX1ZhKpNKZSxPlXY4 JIbwyJZD7tfGAHSNKBDsL5YbGE5ydLtlH66+oXrQ7c45Kuwt+UlJ6u+IahaHbSNWJUDu jjaHsDNmR0cjdVtmwGJ+Z5XzoV22i9r7IJOVpt4/TFZiB5dXhSgQVTKQ3biQp+6XpL1o /ss3v7MX3oUWQc93xUkjqTxROOXZ8UVojNBUM7aCQhyv5AVcovbm9dHyGqE2wGRujm2f FQM3TzcuG5O99ybBu9Zl+O2tucdD0Q1WCevUpDTv9IjNb7C4VlhJ0Hq/8SvNSKb5+TkF 2jdg== X-Gm-Message-State: AOJu0YzbdyZI6O7Lr+SQuhDiSv1bwMDMdjIT9hf0u67W3yQz7DinP7MQ hlcqMAYxdLdOdP+0Bu7DZcw28KQqVFhbCyLnkKy6hOOaXTwti5cDZfWWa9H8aQwvtMtWnvb5hOH 6Xe4XtV8X+VfmxZfzpk0M3tUICSD0nkHtmfjNKg7YrBlSv8iBZT8/+ZbW43nIuwgpxOhUb1vP9N E8RZ3yaW4qzoBBq10f1TVxvk2AY1ypk1HXU/D2ZuBsX6kN X-Received: from dycoh22.prod.google.com ([2002:a05:7301:da16:b0:2ed:b77f:b02a]) (user=ctshao job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7300:e7a2:b0:2ea:b85c:153d with SMTP id 5a478bee46e88-303986948camr7032909eec.27.1779144545297; Mon, 18 May 2026 15:49:05 -0700 (PDT) Date: Mon, 18 May 2026 15:47:48 -0700 In-Reply-To: <20260518224819.1247382-1-ctshao@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260518224819.1247382-1-ctshao@google.com> X-Mailer: git-send-email 2.54.0.746.g67dd491aae-goog Message-ID: <20260518224819.1247382-2-ctshao@google.com> Subject: [PATCH v7 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, james.clark@linaro.org, thomas.falcon@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 --- tools/perf/util/evsel.c | 80 ++++++++++++++++++++++++++++++----------- 1 file changed, 59 insertions(+), 21 deletions(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 2ee87fd84d3e..1f120c27e5d7 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -3928,7 +3928,8 @@ 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; @@ -3969,29 +3970,64 @@ 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) + 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); + if (fdinfo_fd == -1) continue; - cmdline_size = read(cmdline_fd, buf, sizeof(buf) - 1); - close(cmdline_fd); - if (cmdline_size < 0) + fdinfo_size = read(fdinfo_fd, buf, sizeof(buf) - 1); + close(fdinfo_fd); + 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); @@ -4109,7 +4145,9 @@ 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) -- 2.54.0.746.g67dd491aae-goog