From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 B28EA43E9FD for ; Tue, 4 Aug 2026 17:43:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785865403; cv=none; b=nsy8m0Bwg0DFyUJ5R/DFL1bkQ2xEczWXLRtxZdBAEhIuoMM5hI1+ebyA89p4j6ndlrvtwCvnolwL00jEN6bGTX195uWlzXv3OnymgU57BkPmaP7l2h8MyvgZLWd/iwH/bF/ysKK/3qSSQYbv9GHudww+CoXh/FvQADndAovvyDw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785865403; c=relaxed/simple; bh=LmtkPNT7OA50pIWREDZmmsPOFGwY+6prfDBN425VXOE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=q9ikDMYx/TmKNA4xMy3KPqqJZk9dB10O2oTz0cromHx+ZZTE93ovn6Sz9ZJxONRueQomLUVqp/3W9TilyN73DWb9oWXnrkqX/ah+QAd1imYczQZyTcs56Hf+lB0iyawsSynjT7dtraJZlHYLZAScgxN49zWWlhv9mi3ksgRmS7w= 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=N2Yie7rr; arc=none smtp.client-ip=170.10.133.124 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="N2Yie7rr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1785865400; 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=5HNEiOmcNvNIRoVh955nnmNdw9FkXY2EZFVZ3Ml4Ei0=; b=N2Yie7rrN/GVYokZrfmqpA8/FrJzMRxKLaqLCSeaZXLJR/iSaL2SbvAGSnVUC94koVz+e5 FJ1vN7jde0XUlas43aXMBlCvYxSythJpipf7whUcPBE6LGDoQkoracAGDSVHAHrB6vnU9W pZZyRvrMUbfRVEfj/MUOc7GBaFqYd3w= 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-556-okZE7ZHSP6O-FyeAqpchyQ-1; Tue, 04 Aug 2026 13:43:14 -0400 X-MC-Unique: okZE7ZHSP6O-FyeAqpchyQ-1 X-Mimecast-MFC-AGG-ID: okZE7ZHSP6O-FyeAqpchyQ_1785865393 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 AD33A19560BB; Tue, 4 Aug 2026 17:43:12 +0000 (UTC) Received: from vschneid-thinkpadt14sgen2i.remote.csb (unknown [10.44.34.30]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 91FF7195608E; Tue, 4 Aug 2026 17:43:08 +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 v4 0/6] tracing/osnoise: Track IPIs Date: Tue, 4 Aug 2026 19:42:32 +0200 Message-ID: <20260804174242.2288433-1-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/v4 Cheers, Valentin Revisions ========= v3 -> v4 ++++++++ o Rebased onto v7.2-rc4 o Fixed 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 (6): 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: Unconditionally clean any pre-existing filters for user-provided events rtla/osnoise: Trace IPI events when recording a trace file Documentation/tools/rtla/rtla-osnoise-top.rst | 4 + tools/tracing/rtla/src/cli.c | 1 + tools/tracing/rtla/src/cli_p.h | 3 + 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 | 4 + 9 files changed, 244 insertions(+), 4 deletions(-) -- 2.55.0