From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (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 96B97221F1C for ; Fri, 21 Nov 2025 23:10:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763766621; cv=none; b=dy/Hd5cNhOsCs847422Jiu39QEEiIP01D3mSRHXAqTcOhbdYx09wA/OJjz76cm9cD9i1G2QUr32sbwmWaHzeDqv3gqf7cyynQuXl3CpWMlU6XpJ2+7iyanetfRuqIYKdE6kmFV0Wz0aFxfJMNkXwURsjflqmQ+cHNMj0oRIDxVg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763766621; c=relaxed/simple; bh=8bWhIzEE2kOCM2/P4siDh4lmVU3/GWQ9Z1Vge3A2ZaM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=N2+eY3ZWPGfK5K9LUkaQxaSAh4ST/j4FUSp32Mxl+YmmyZh+W+CrcZiY9VaK/y7v7hSD1n5fuWkaoFSNS1gWivBHUzRjVR1FiVy4Nim3d6eyy7UzL5PjlxNA2YXAOdFrTyO8/3rvxQIgfgvGm+7I33edKPkkveCDQ8vCm2CpBrA= 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=LDRbe6Gy; arc=none smtp.client-ip=209.85.215.202 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="LDRbe6Gy" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-b62da7602a0so2415696a12.2 for ; Fri, 21 Nov 2025 15:10:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1763766611; x=1764371411; 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=5b2DOngf45K4pr9iLY35IcW9cBrxBxPbnXC9KlOB26c=; b=LDRbe6GybRAOnGdkEO+zKAVLrXAOeH+v2MuxHZ2jmF+GdXnRzJu9NyzXfkQXOkIlm/ jC/Z93rjNV+cdNBkFixN8/4//UdFNdDx0wU2RZwSgLlOz6uVh/CNzg+KEHtRanf6WSju AlqKhvsAV4L/Khb+YPM798GPEPAJJkJmgM+KRA/XjjM93+Nz+6lsjvPeBLCcorfRHRZM YI1rth0cq5uphZc0YYz79KAXFKW3aKrd89i7HQoNCjZUcHVfCigz1fu5ZxiJEhi6M+CI pba9HgHe5moO0xJAZ5rEH1IlaXi/0hDH1PEnWmCut07YLHaBVBxd/SRt6jCKuOMgdC+9 rDYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763766611; x=1764371411; 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=5b2DOngf45K4pr9iLY35IcW9cBrxBxPbnXC9KlOB26c=; b=n92IOeWAzRVTxgVhnBEvU9PvVMnIQ79gHCTGzOSMXqZfY6mZlTfWDvWeZPx85MJLLH BrVy0Pz0Nmqzo41sDOGTH6oPQ8aArl972HkRPenp7BMb0Vb3nARhDXx+xSLtDnz3VtuZ uhXh8e56cJI6imFPU13lFH1Op4sW7Iu18+LGqjFHlx6qfojHjeWutUHDLSXV6O15Z51Q XBN55jqkkE5PVfteF24O3Nx49uSjUHwz/DwbMPVYhHTWwJvbT2lJBEKd1MooOcRHSMq6 K3mmoI4ykNdaqxLJaJOuQVCcul+rD83sP7zYpCR9ho1k/cRfmkICyHn/CWFg5RZOCewc ow4Q== X-Forwarded-Encrypted: i=1; AJvYcCXicpCdenDx1gPHspd4KT1P9r0GWzMxfx3N4xQ8ZWeGWgKslKxwm5fNEH1WwJxGyeTpo+nd+HtFNear5PFgyS3u@vger.kernel.org X-Gm-Message-State: AOJu0YzS+1QYpUAaqyTcfI8aFVkyXUh8RGaDJbIx9S2l5c7u5w+QQcro yUVCC3NkQX3y700CvC7Jc7JJiyoZmZyvnDq7P8Dj/iDgXmQj2fOnq8RGSpMQCc0iz52DzVz4vUb UyXFiEA== X-Google-Smtp-Source: AGHT+IGylgxQzgTzR8vCzvcryIe4d4Y+gnzkKFo3DXktMIlzTpkf5SRCaUVEZdGi/cXH+z3M3SolRzieAsk= X-Received: from dyaa12.prod.google.com ([2002:a05:693c:40cc:b0:2a4:7453:cd4e]) (user=ctshao job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7300:3c1e:b0:2a4:3593:ddf0 with SMTP id 5a478bee46e88-2a719fbd09bmr1625100eec.29.1763766610602; Fri, 21 Nov 2025 15:10:10 -0800 (PST) Date: Fri, 21 Nov 2025 15:09:12 -0800 In-Reply-To: <20251121230951.3240124-1-ctshao@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251121230951.3240124-1-ctshao@google.com> X-Mailer: git-send-email 2.52.0.rc2.455.g230fcf2819-goog Message-ID: <20251121230951.3240124-2-ctshao@google.com> Subject: [PATCH v5 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, thomas.falcon@intel.com, howardchu95@gmail.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 --- v5: No change. v4: lore.kernel.org/20250603181634.1362626-2-ctshao@google.com/ 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 aee42666e882..059792a978a8 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -3732,7 +3732,8 @@ 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; @@ -3773,29 +3774,61 @@ 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); @@ -3914,7 +3947,9 @@ 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) -- 2.52.0.rc2.455.g230fcf2819-goog