From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 2A22E48551B for ; Wed, 2 Sep 2026 12:40:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788352823; cv=none; b=sfmQ5FLL/HyFcwIQwSKUxFPLEEQTv+uzjzgpVgh+LbRd7XTQIvKmc1/XM07Ujp6ILFt0Z5e024FJ+eQKbEg2D5fGU5XORAMZuTAqOjmVsOAXxutNvaaIVEfnIe7xJ2baQFJ8a6h9dSyDaQ5d+ZT3bLOM27f+xCEW/vJ3GrvwjJY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788352823; c=relaxed/simple; bh=6ldI2oWhqqciz/d7Opr319MQFKF+Zkje0h47Bfp/ifQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=bXiWc2T2rfbIWd7ZoXUUasIFwoAR2/tZacvF18KCRTz8683SuoEMMYPd9Gw/JpznzXZ7PY4h27gAfdbX4xan9iZC/wUFWX7sY3k37hpXEpMPQnRpVubB08HUFJYdbVcyBwzCk+iCA06FtJJ3JLIk6Fb8Y1dK/k4uMIbRvtXhYvc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=GY107tkB; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GY107tkB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1788352821; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=DPabCix+pfnXhCWbiytjvC43Wtk1N7h4RXWap1DJTBc=; b=GY107tkByJncsgwneMH3ug3JoZhyqsPAvyw9P1k1SdXSata77/VQR2g0n/QsDllWcCToa9 gQe9xQ74LP5IbaQ33hQMxdEhpTvrHieJ6GHhQ5UHuHhBPMVb2JPjvvCM6qZ/cRJ6V6mqRw WzzXUzzMaCgbuitI3B9UmZ9Sv/Tqb2U= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-435-m_Uqogk1PoWtCeGweqR7dQ-1; Wed, 02 Sept 2026 08:40:17 -0400 X-MC-Unique: m_Uqogk1PoWtCeGweqR7dQ-1 X-Mimecast-MFC-AGG-ID: m_Uqogk1PoWtCeGweqR7dQ_1788352816 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 651F3192DD61; Wed, 2 Sep 2026 12:40:16 +0000 (UTC) Received: from vschneid-thinkpadt14sgen2i.remote.csb (unknown [10.44.33.19]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1E0121955F72; Wed, 2 Sep 2026 12:40:11 +0000 (UTC) From: Valentin Schneider To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Tomas Glozar , Costa Shulyupin , Crystal Wood , John Kacur , Ivan Pravdin , Jonathan Corbet Subject: [PATCH v5 0/8] tracing/osnoise: Track IPIs Date: Wed, 2 Sep 2026 14:39:29 +0200 Message-ID: <20260902123942.695822-1-vschneid@redhat.com> 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 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Hi folks, So I've seen a few times now reports of latency spikes caused by IPIs, usually because of isolation misconfiguration, but only detected at the tail of end e.g. a 24h timerlat run. It's not because those IPIs are rare, but rather that they don't by themselves cause a monitered CPU to reach the latency threshold, it's usually a combined interference that gets us there. I'd like to make it easier to detect such misconfigurations and thus IPIs hitting supposedly-isolated CPUs. I initially kludged a timerlat option to stop tracing as soon as an IPI was sent to a monitored CPU, regardless of the latency threshold. It sort of did the trick, but Tomáš convinced me timerlat wasn't really the place for that. Patches are available at https://gitlab.com/vschneid/linux.git -b mainline/tracing/osnoise-ipi-userspace/v5 Cheers, Valentin Revisions ========= v4 -> v5 ++++++++ o Made events processing follow user-specified order v3 -> v4 ++++++++ o Rebase onto v7.2-rc4 o Fix changelog typo v2 -> v3 ++++++++ o Dropped the short-form -i option to leave it free o Re-arranged top header printing o Fixed tracefs_event_file_write() return value handling o Changed IPI filtering to allow it to gracefully fail on older kernels o Added filter clearing for -e events to ensure a known state v1 -> v2 ++++++++ o Dropped the in-kernel osnoise_sample changes and made it all userspace Valentin Schneider (8): rtla/osnoise: Add IPI tracking cmdline option rtla/osnoise: Record IPI count in osnoise top rtla/osnoise: Leverage IPI event filters when tracing a subset of CPUs rtla/osnoise: Allow IPI filters to gracefully fail rtla: make struct trace_events double linked rtla: Enable and disable events in the user-defined order rtla: Unconditionally clean any pre-existing filters for user-provided events rtla/osnoise: Trace IPI events when recording a trace file Documentation/tools/rtla/common_options.txt | 9 +- Documentation/tools/rtla/rtla-osnoise-top.rst | 4 + tools/tracing/rtla/src/cli.c | 1 + tools/tracing/rtla/src/cli_p.h | 7 +- tools/tracing/rtla/src/common.c | 2 +- tools/tracing/rtla/src/common.h | 3 +- tools/tracing/rtla/src/osnoise.c | 72 +++++++- tools/tracing/rtla/src/osnoise.h | 4 + tools/tracing/rtla/src/osnoise_top.c | 155 +++++++++++++++++- tools/tracing/rtla/src/trace.c | 28 +++- tools/tracing/rtla/src/trace.h | 1 + 11 files changed, 276 insertions(+), 10 deletions(-) -- 2.55.0