From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 738DA22156A; Tue, 8 Jul 2025 02:00:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751940051; cv=none; b=io72vqv5pc42RqPjIoCd8+NrCE3KecSYPIgK4yDAebCo1roFy7j4sVtaiyxGLS9k+8ciyfIew9xrb9ZmfVVN+Gp/N/L0Xt2/sxCJasKqqKUIs8Bb+bsPXsi49CZJOzGQLL5dm9LhlTDpNh1Q/GBIqnC29LtqBAN774eMsfhP+Y0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751940051; c=relaxed/simple; bh=uOx5DfUnBLxP9fI1uU9zO1GwRE8LdxHgs3BL/mHcvYk=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=EHRerh7BYaQrU375CcGyezWO9Cf+dJCu7UHqw2u3pfsS/IZr0qNGR2Yhk++0NdJV8IsbeE5/SLAn+ILL56avRWsb0YIxogqZBt292IXERSewc54zLrwda6/ATYP6AGXEMYiVrVXjAOQR+a6XBeZ+glbNLL0a80JksNEvfwUQ/GM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HQ5FYcqS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HQ5FYcqS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B4C0C116C6; Tue, 8 Jul 2025 02:00:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751940051; bh=uOx5DfUnBLxP9fI1uU9zO1GwRE8LdxHgs3BL/mHcvYk=; h=Date:From:To:Cc:Subject:References:From; b=HQ5FYcqS7Ll/9x2LOOx412xxuL+W8sAv5GMDLCJD6LddvG/cChir7tnX2lO/ZAHSI qN/TKdyE0G5vD32IggkAC83x8c4rOCGEYG0a+apDgktvhwOm6rTLpdV9NjlMmAhRZi +poaZwePQv9+JcarxaXsJxeI7G1EDZkBieojAPrWKl4jjHvrjPb4kbePqs7LV1iOT+ Xjz3L194tDzVg0PrptFjnM9o2eOYpC3PbOBbxDvyyz2Y6y9S9n0PkE9if1nMmvtj4c JIEsFVSyxCW0WrXh4rkdgxapN3/3/corRmU/N5wY/GRwTZ7JPMTTtqFOgeuawbehG4 5Xzlo3Xv5dN4w== Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1uYxdb-00000000D87-2Sxl; Mon, 07 Jul 2025 22:00:51 -0400 Message-ID: <20250708020051.439871837@kernel.org> User-Agent: quilt/0.68 Date: Mon, 07 Jul 2025 22:00:12 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org Cc: Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Peter Zijlstra , Ingo Molnar , Jiri Olsa , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton , Jens Axboe , Florian Weimer , Sam James Subject: [PATCH v13 09/11] perf record: Enable defer_callchain for user callchains References: <20250708020003.565862284@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Namhyung Kim And add the missing feature detection logic to clear the flag on old kernels. $ perf record -g -vv true ... ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) { sample_period, sample_freq } 4000 sample_type IP|TID|TIME|CALLCHAIN|PERIOD read_format ID|LOST disabled 1 inherit 1 mmap 1 comm 1 freq 1 enable_on_exec 1 task 1 sample_id_all 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 defer_callchain 1 ------------------------------------------------------------ sys_perf_event_open: pid 162755 cpu 0 group_fd -1 flags 0x8 sys_perf_event_open failed, error -22 switching off deferred callchain support Signed-off-by: Namhyung Kim Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) --- tools/perf/util/evsel.c | 24 ++++++++++++++++++++++++ tools/perf/util/evsel.h | 1 + 2 files changed, 25 insertions(+) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 6176c31b57ea..c942983b870e 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1076,6 +1076,14 @@ static void __evsel__config_callchain(struct evsel *evsel, struct record_opts *o } } + if (param->record_mode == CALLCHAIN_FP && !attr->exclude_callchain_user) { + /* + * Enable deferred callchains optimistically. It'll be switched + * off later if the kernel doesn't support it. + */ + attr->defer_callchain = 1; + } + if (function) { pr_info("Disabling user space callchains for function trace event.\n"); attr->exclude_callchain_user = 1; @@ -2124,6 +2132,8 @@ static int __evsel__prepare_open(struct evsel *evsel, struct perf_cpu_map *cpus, static void evsel__disable_missing_features(struct evsel *evsel) { + if (perf_missing_features.defer_callchain) + evsel->core.attr.defer_callchain = 0; if (perf_missing_features.inherit_sample_read && evsel->core.attr.inherit && (evsel->core.attr.sample_type & PERF_SAMPLE_READ)) evsel->core.attr.inherit = 0; @@ -2398,6 +2408,15 @@ static bool evsel__detect_missing_features(struct evsel *evsel, struct perf_cpu /* Please add new feature detection here. */ + attr.defer_callchain = true; + attr.sample_type = PERF_SAMPLE_CALLCHAIN; + if (has_attr_feature(&attr, /*flags=*/0)) + goto found; + perf_missing_features.defer_callchain = true; + pr_debug2("switching off deferred callchain support\n"); + attr.defer_callchain = false; + attr.sample_type = 0; + attr.inherit = true; attr.sample_type = PERF_SAMPLE_READ; if (has_attr_feature(&attr, /*flags=*/0)) @@ -2509,6 +2528,11 @@ static bool evsel__detect_missing_features(struct evsel *evsel, struct perf_cpu errno = old_errno; check: + if (evsel->core.attr.defer_callchain && + evsel->core.attr.sample_type & PERF_SAMPLE_CALLCHAIN && + perf_missing_features.defer_callchain) + return true; + if (evsel->core.attr.inherit && (evsel->core.attr.sample_type & PERF_SAMPLE_READ) && perf_missing_features.inherit_sample_read) diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index 6dbc9690e0c9..a01c1de8f95f 100644 --- a/tools/perf/util/evsel.h +++ b/tools/perf/util/evsel.h @@ -221,6 +221,7 @@ struct perf_missing_features { bool branch_counters; bool aux_action; bool inherit_sample_read; + bool defer_callchain; }; extern struct perf_missing_features perf_missing_features; -- 2.47.2