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 9FA623B2D1F for ; Mon, 15 Jun 2026 06:17:15 +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=1781504236; cv=none; b=g0DtrfV0hHXLfr5Cb0jiHeZvyrqYW3UcXC7W64pEaNlydK1a6bljEqAc7zO5/RNM38sdWwHDX0Ix3nd+sfcfeCsP+jUCmt+219IBRLhonwc8nwEuFgilU+p1Q1vPX5XvB1+gcBWc0JfLghVmhdf15p4QAuMBDB8hUnA088tDiew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781504236; c=relaxed/simple; bh=USHa9Za9v3JvVyp8hT1Fn6p/kwcudz73UgjkmHHqV3A=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Cjugi4eoZWxYd4p2XRTxMWjUCnMm3KFbVLXSIDBrQ8M9K6v+b3UshXe6jnY7sFBVdyZH8cJr+KvOJV6ZJzz1RFY4gUUEiwIkBPTeQ8e5/BAZfxJXIpWT6DsTYX2VmEIL0Yh1U9rFEJDRuPJO8wUItgxqV7yU7N/aU0qARomQ10A= 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=anfH55nE; 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--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="anfH55nE" Received: by mail-dy1-f202.google.com with SMTP id 5a478bee46e88-304df51ff3eso6493565eec.0 for ; Sun, 14 Jun 2026 23:17:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1781504235; x=1782109035; 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=vyyNdhBg09PfHKWAasLSBP18KQPTWQY9AF1LP/3RnBE=; b=anfH55nE1IGSew4dLcNUwMLn0P435lt3MBMjtmCBRR2O7exvAkqCVOacz/abFIBKsU /IX5GqalwiyFru8dPN807xpf4+oTaIl3J15B7MwiG7MHMM0MENKuCVHPiRHudQB56lcF lZHFZQaBwyUOf9qWKchZ5HtF+4b5kcclfqzVAD16f85LGRBSJnEikYvykvDzZt7WoEUD GaJ4znh70/J+L8Nw3xbBDoKezQ9vqCwZbfyv4WUEq5tG8Cmf+KcH/XSfJj8ul+ViMFYo 73nDhEj3t9Te956SZKBsenc3IrTYFO3hlV2rWmIY7CoPup3+nxMfb2al6c4H07+kBnkB w67w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781504235; x=1782109035; 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=vyyNdhBg09PfHKWAasLSBP18KQPTWQY9AF1LP/3RnBE=; b=Hbo2mAeFBOWLflOZ3wtweWrPPQAS00mt7oHDa4qKa/ThAUIQQzrBMkbB6BB+LbRuLr iwg8cVdRIixKGy5NEgLUOJWSB1OxvQezH05ui/s8wWeIFGQhLpNoSzpe0KFfu3g/hFeK P1Sqo+3NUO7zmBhdNJJDtAOaBncTw0g2bsZ9nxXKxcERr0w/1kscTXmZNzpZJ0Y0rPb+ NANZK2IsQiL2hyyGj7mBnW7LCRWzEeWlTBQHJWOVSuaFCnYz85C7z1OGdWcMcM+c9MXe R2/7C+qlIJGte6FBq4sAGFOOXd6h2KQi03ApBk0KTyv79N49hcTJwBx3QZBZEsxclBtD h4rA== X-Forwarded-Encrypted: i=1; AFNElJ9q81yVBk3avxxcN8awpZtrY3gOGp5HYct9gA2DyiCNmgR//Jhr+6+eyn17IBnVXoiy6VGIZzBv4CtPsf8=@vger.kernel.org X-Gm-Message-State: AOJu0YxzyE+Xu7MSzN3pVKBGnV35ADTFAqVFNNxF69tztyUHBY/JpEIJ IJNaVjEuxHMAbhAkrXKthDg4Qz8ApQ6WLY1jvnomL6Wq5rvGS4dvDfxccRiBtEGMOf8Kh2kBldP kI95NqpD8WQ== X-Received: from dycqr8.prod.google.com ([2002:a05:7300:ff48:b0:2f7:767f:edc0]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7300:fd14:b0:304:8881:b82 with SMTP id 5a478bee46e88-3081ff4b721mr5648810eec.1.1781504234622; Sun, 14 Jun 2026 23:17:14 -0700 (PDT) Date: Sun, 14 Jun 2026 23:16:30 -0700 In-Reply-To: <20260615061631.2382079-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260615002812.2234795-1-irogers@google.com> <20260615061631.2382079-1-irogers@google.com> X-Mailer: git-send-email 2.54.0.1136.gdb2ca164c4-goog Message-ID: <20260615061631.2382079-21-irogers@google.com> Subject: [PATCH v19 20/20] perf python: Add LiveSession helper From: Ian Rogers To: irogers@google.com, acme@kernel.org, namhyung@kernel.org Cc: adrian.hunter@intel.com, alice.mei.rogers@gmail.com, dapeng1.mi@linux.intel.com, james.clark@linaro.org, leo.yan@linux.dev, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, tmricht@linux.ibm.com 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 --- v12: - Fixed `setup_python.sh` `PYTHONPATH` prepend logic to cleanly append to existing paths. 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. v8: - Drain all events from a CPU before moving to the next. --- tools/perf/python/perf_live.py | 59 ++++++++++++++++++++++ tools/perf/tests/shell/lib/setup_python.sh | 13 +++++ 2 files changed, 72 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..616b5f657463 --- /dev/null +++ b/tools/perf/python/perf_live.py @@ -0,0 +1,59 @@ +# 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.""" + try: + self.evlist.open() + 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: + for _ in range(1000): # Limit to 1000 events per CPU per poll to prevent starvation + try: + event = self.evlist.read_on_cpu(cpu) + except TypeError as e: + if "Unknown CPU" in str(e): + # CPU might be unmapped or offline, wait for mmap event + break + if "Unexpected header type" in str(e): + # Ignore valid but unsupported event types + continue + raise + + if event is None: + break + + if event.type == perf.RECORD_SAMPLE: + self.sample_callback(event) + except KeyboardInterrupt: + pass + finally: + self.evlist.close() diff --git a/tools/perf/tests/shell/lib/setup_python.sh b/tools/perf/tests/shell/lib/setup_python.sh index a58e5536f2ed..2173215a0517 100644 --- a/tools/perf/tests/shell/lib/setup_python.sh +++ b/tools/perf/tests/shell/lib/setup_python.sh @@ -14,3 +14,16 @@ then echo Skipping test, python not detected please set environment variable PYTHON. exit 2 fi + +# Set PYTHONPATH to find the in-tree built perf.so first, avoiding system-wide perf.so +if [ -n "$PERF_EXEC_PATH" ] && [ -d "$PERF_EXEC_PATH/python" ]; then + PYTHONPATH_DIR="$PERF_EXEC_PATH/python" +elif [ -d "$(dirname "$0")/../../python" ]; then + PYTHONPATH_DIR="$(dirname "$0")/../../python" +elif [ -d "$(dirname "$0")/../python" ]; then + PYTHONPATH_DIR="$(dirname "$0")/../python" +fi + +if [ -n "$PYTHONPATH_DIR" ]; then + export PYTHONPATH="$PYTHONPATH_DIR${PYTHONPATH:+:$PYTHONPATH}" +fi -- 2.54.0.1136.gdb2ca164c4-goog