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 B9C0C3D3301 for ; Thu, 23 Apr 2026 03:56:26 +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=1776916588; cv=none; b=a3I85QI7VKOAY6YuTY6GUvUDaW1wfci6Ts///BJZGj4JTUO4MCvoF35L5z2FxVejLUnrClXb/d+ceAYP38iFlDEB/nFjqvhQQjtm8pMh+CPevorOAZ/lj3auj4V74gvXp5AJsBT27vh1dGCUZvzl9lS4KlfzqHlNGxxt1Zi691w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776916588; c=relaxed/simple; bh=WFDMhKuu3BFqFsv2w40b0o7hPwy4zzx9X3skPUxJuJE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=oxzqpTokZbij3LoyqHpd8XEotKd2IBFpRyX/VYavCFm0bcP8Dsl36RWYghXWDcrLZ+aA8/4JeeKhVCLEoI+h7aO+r6l0fmAbkOKk1K0ELaIvNY8a8dcj7GDwvwlMeFb2gIH20egzTLfz0CItadtlrTzNpWKan4b6T5ZXB0t9NOo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=t2kgTvnE; 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--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="t2kgTvnE" Received: by mail-dy1-f201.google.com with SMTP id 5a478bee46e88-2c0ba59a830so9746488eec.0 for ; Wed, 22 Apr 2026 20:56:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1776916586; x=1777521386; 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=PmfkDHgGkhhc8Ci3nU27rOXJ2A7e5StlaPZmf/zqGxg=; b=t2kgTvnENXaALYbOANaLx3TlMIbPodwGy6G14Syf+wuqO5BotSz3ZA4JIow7EE+0Rf FqvxG2EzBA5SOczFhXZFHCfvfjIxjUoqmkMtViUgCFTIf25WX6WFi9ve6SVY7zAMV0uQ eUcMWYrvq8eXazaBAkCx9x24vd9R5PZVRuVrX0imW9D5BJxIXnA/KfhzRlpHSQg7jdSw Lslsf4hZbs6BzvUyfyYP+3KFXx59ApF+Xxz59xmcqkRiHSBYDgbgyEAfsY02Jy/2nwT2 kYsRotXhe5jknFxgDCBcVcNF9XaF0frH33hkAZZIf4Kc2MJmT8bbnPQXSWQHQKZDB/lC E4NQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776916586; x=1777521386; 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=PmfkDHgGkhhc8Ci3nU27rOXJ2A7e5StlaPZmf/zqGxg=; b=kLTDce+9ND2a6d1oYteUCLKiK0pqvZfO+cKXBJdqGynUHXAuOqfju7TIdXRklSQOfL Fefzfi4U4pSXXWWj5lF7ve0ASqCA/kUQ/1mYiqRczyrkwAQhoCYFcPL97QvT3TzlAuiE 1cE9C4mSUqOMtjUce5ON1eIu01cJJyuU9vD9DCji6tHm2N+ZqipI82qwtPCWjv8v1tvB ry42UiGgtYfrVt/Xa/+/X8XxgQhfsCKgYAIHfIBHBPpjgJu/KCT6IlhIIiWfN4tphpfL SqEEKALVpXMv8h0mbcv2WBV2VWHSpaTL6k/zA5ph6CRkg3fAVZR61KUxSGwd//RA7GPg YgGg== X-Forwarded-Encrypted: i=1; AFNElJ9t9pkjBddTG+fODxD1A0PvOrRQRmnGBucB9n7F+v/NAeGcYEX0cBQ1SPQb0rLw3kIOn9c+welc35ayMAg=@vger.kernel.org X-Gm-Message-State: AOJu0Yw+RdcZUc1Jh8A/LoaZRK6C8u3qH6s3fGfzKBEUeurS4a53LcG2 3UuKKU0K6EHmHUMt4QIC6t19rUpy7iJN1I4hAh6uteLMsrv18nicBnSJd2/BEDFEfAScZ07Cqh1 k6Ti5IsM0wg== X-Received: from dybso7.prod.google.com ([2002:a05:7301:6907:b0:2d8:e3a6:d707]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7300:dc05:b0:2c0:bfe3:b95c with SMTP id 5a478bee46e88-2e466044086mr12419456eec.4.1776916585477; Wed, 22 Apr 2026 20:56:25 -0700 (PDT) Date: Wed, 22 Apr 2026 20:54:50 -0700 In-Reply-To: <20260423035526.1537178-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260419235911.2186050-27-irogers@google.com> <20260423035526.1537178-1-irogers@google.com> X-Mailer: git-send-email 2.54.0.rc2.533.g4f5dca5207-goog Message-ID: <20260423035526.1537178-24-irogers@google.com> Subject: [PATCH v2 23/58] perf python: Add LiveSession helper From: Ian Rogers To: irogers@google.com, acme@kernel.org, adrian.hunter@intel.com, james.clark@linaro.org, leo.yan@linux.dev, namhyung@kernel.org, tmricht@linux.ibm.com Cc: 9erthalion6@gmail.com, adityab1@linux.ibm.com, alexandre.chartre@oracle.com, alice.mei.rogers@gmail.com, ankur.a.arora@oracle.com, ashelat@redhat.com, atrajeev@linux.ibm.com, blakejones@google.com, changbin.du@huawei.com, chuck.lever@oracle.com, collin.funk1@gmail.com, coresight@lists.linaro.org, ctshao@google.com, dapeng1.mi@linux.intel.com, derek.foreman@collabora.com, dsterba@suse.com, gautam@linux.ibm.com, howardchu95@gmail.com, john.g.garry@oracle.com, jolsa@kernel.org, jonathan.cameron@huawei.com, justinstitt@google.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, mike.leach@arm.com, mingo@redhat.com, morbo@google.com, nathan@kernel.org, nichen@iscas.ac.cn, nick.desaulniers+lkml@gmail.com, pan.deng@intel.com, peterz@infradead.org, ravi.bangoria@amd.com, ricky.ringler@proton.me, stephen.s.brennan@oracle.com, sun.jian.kdev@gmail.com, suzuki.poulose@arm.com, swapnil.sapkal@amd.com, tanze@kylinos.cn, terrelln@fb.com, thomas.falcon@intel.com, tianyou.li@intel.com, tycho@kernel.org, wangyang.guo@intel.com, xiaqinxin@huawei.com, yang.lee@linux.alibaba.com, yuzhuo@google.com, zhiguo.zhou@intel.com, zli94@ncsu.edu Content-Type: text/plain; charset="UTF-8" Add LiveSession class in tools/perf/python/perf_live.py to support live event collection using perf.evlist and perf.parse_events, avoiding the need to fork a separate perf record process. Signed-off-by: Ian Rogers Assisted-by: Gemini:gemini-3.1-pro-preview --- v2: 1. Fixed File Descriptor Leak: I moved self.evlist.mmap() inside the try block so that if it raises an exception, the finally block will still be executed and call self.evlist.close() , preventing file descriptor leaks. 2. Handled InterruptedError in poll() : I wrapped the poll() call in a try-except block to catch InterruptedError and continue the loop. This prevents the live session from crashing on non-fatal signals like SIGWINCH . 3. Added evlist.config() : I added a call to self.evlist.config() in the constructor after parse_events() . This applies the default record options to the events, enabling sampling and setting up PERF_SAMPLE_* fields so that the kernel will actually generate PERF_RECORD_SAMPLE events. 4. Enable the evlist and be robust to exceptions from reading unsupported events like mmap2. --- tools/perf/python/perf_live.py | 48 ++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100755 tools/perf/python/perf_live.py diff --git a/tools/perf/python/perf_live.py b/tools/perf/python/perf_live.py new file mode 100755 index 000000000000..d1dcbab1150b --- /dev/null +++ b/tools/perf/python/perf_live.py @@ -0,0 +1,48 @@ +# SPDX-License-Identifier: GPL-2.0 +""" +Live event session helper using perf.evlist. + +This module provides a LiveSession class that allows running a callback +for each event collected live from the system, similar to perf.session +but without requiring a perf.data file. +""" + +import perf + + +class LiveSession: + """Represents a live event collection session.""" + + def __init__(self, event_string: str, sample_callback): + self.event_string = event_string + self.sample_callback = sample_callback + # Create a cpu map for all online CPUs + self.cpus = perf.cpu_map() + # Parse events and set maps + self.evlist = perf.parse_events(self.event_string, self.cpus) + self.evlist.config() + + def run(self): + """Run the live session.""" + self.evlist.open() + try: + self.evlist.mmap() + self.evlist.enable() + + while True: + # Poll for events with 100ms timeout + try: + self.evlist.poll(100) + except InterruptedError: + continue + for cpu in self.cpus: + try: + event = self.evlist.read_on_cpu(cpu) + if event and event.type == perf.RECORD_SAMPLE: + self.sample_callback(event) + except Exception: + pass + except KeyboardInterrupt: + pass + finally: + self.evlist.close() -- 2.54.0.rc2.533.g4f5dca5207-goog