From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dy1-f202.google.com (mail-dy1-f202.google.com [74.125.82.202]) (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 6B38F3890F1 for ; Mon, 18 May 2026 17:42:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779126161; cv=none; b=d1PzpC5n6TkrUFJ8COUIOV4+qu9n7CCJ0hTv7DB37DBPVv1txiiOaZ63mR6Lww16hsuWrd01a9gNi9u/bmyFpNvSnmyOzSUcROQVZfj3D18XMglh2arLms+9RanEYbqei/Z0B7ovL6vrKZskhR6XIpw/daBciLB4hiT84y4vzOA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779126161; c=relaxed/simple; bh=1pK2kNDo7FlTcm5GFv1e1uqvoBNFJ5/Xo7pM5YWk7tQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=hv/dw3w6eG/+9gmPlu8+hSz5PfLb5BV7M2qFIMBuubjO8b97x6TFCo6Wn7RxZ6vs9TOvsJOKi+KcHh1UeEBHx3HDojipXn+3nDptx8flI99cgKxBARpUIGHYNAzCWD9TlCcMvhgUaJMrkO+Q6iTlJPlUcjtY2zHkmXitt6Bpq5Y= 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=I+ElaFvk; arc=none smtp.client-ip=74.125.82.202 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="I+ElaFvk" Received: by mail-dy1-f202.google.com with SMTP id 5a478bee46e88-2c16233ee11so3634940eec.1 for ; Mon, 18 May 2026 10:42:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779126160; x=1779730960; 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=3s6gn9A6S+BcLCMtqy5uGUxbiN41eBzl4dIsLF5YNTg=; b=I+ElaFvkJqRWs2osVR9hZ4dP9WRYBHMp7oPtDvUVj+m5Rredq+6/IvnVhVmZUzifU0 cQWgM4RpoBvgN1NH1Z5R06klyJyqQIUvUE77JOW7IpPbd2UF8ymMeLJuPzGdOYU3XumO l5xYeXex89vogcHAAkVABs5PtjskL+W2YO3gRXqrl16fv3c+uviqS9+FVJdTsMpsvk40 2N2txmhpzgdJNCY+OrFjivK2jUSzzfqYyGS85rsjQU3Qwt+ZdRjmz6WwZczkg2hZBkHv 7xVqu+Ys7rV+fuxxnv947HvR4OpBUIblKzdo7l1Wa/Ng+FVGzQ5gvx0TLhGjae4x+bjX lLgg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779126160; x=1779730960; 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=3s6gn9A6S+BcLCMtqy5uGUxbiN41eBzl4dIsLF5YNTg=; b=Y0NIYdMn8fCIUXUxkyL67s+SwxmwSLV5a8nOdDUWmNNFk/BMtkGApjZ1UQ9E5xWUQO ZfsYmFXpex6wuRje3wrVgMV5Tcpdn9U/QloKiPMogAF/ds8DRf3G3rhFKOTnPumJ33yr 3xZz7iBRAfHJE9P3zqGfsN0B5BruVqOulRnLX1ZCfwUFvvkdO6FkP7KEa+P1xyGSdUq6 Xhvxz1+NeLz7AlRJiSlES4wOPrH76jNsOlGGPampzXXfkxCC+IuvETYz85JkqBIvNzuV pJk5Qi5om7R1lH7uRm3X4LJwf0dJAFYm0p5TCrRbF/T4y+Ae5B3YMX0ZABv5gQ0MTcCb Q/ZA== X-Gm-Message-State: AOJu0YzRttsgGOhB6ZRHQSBhGTHzHlDaCibdbIYAgY5l+8vJDrpvbRuk rrMCjXIfasEZiOQbTO1Ys3zq+PTE/cF8k5Etr4S2gaZq6GCqs+/Bhfa9QCXf9ufY+hlzaLqfBOC bDJbbeOcW9kfDIWc2p1N1CXxP9MwiE+ucSwMXBWx8064Y1CS6gkIhDwhnHb7sHDjc7KrtluMwvx ALduKoF5uIqfR1HrqoaOawLnluEQzwgz6e//nA+ltvGOOE X-Received: from dybor14.prod.google.com ([2002:a05:7301:1f0e:b0:2f2:fc0:8869]) (user=ctshao job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7300:e28b:b0:2c4:dd55:ffc1 with SMTP id 5a478bee46e88-3039816dcfcmr6921674eec.2.1779126159239; Mon, 18 May 2026 10:42:39 -0700 (PDT) Date: Mon, 18 May 2026 10:41:23 -0700 In-Reply-To: <20260518174159.1177549-1-ctshao@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260518174159.1177549-1-ctshao@google.com> X-Mailer: git-send-email 2.54.0.746.g67dd491aae-goog Message-ID: <20260518174159.1177549-2-ctshao@google.com> Subject: [PATCH v6 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 | 79 +++++++++++++++++++++++++++++------------ 1 file changed, 57 insertions(+), 22 deletions(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 2ee87fd84d3e..f6282099320e 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 +3970,61 @@ 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); @@ -4109,7 +4142,9 @@ 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