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 7606F48C3F7 for ; Wed, 15 Jul 2026 15:46:53 +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=1784130416; cv=none; b=TPhP3pi7ELycjnMLNUN4y3p/QHNEFfeoM+136221oClzdsIxsXZl9Jtgh30JtKDjge7fmSD7wnRnEL6Eeu71zkIjqTfTyqpQQckxuK6K3IQB9guETieW3qdT+8aYadIyKsSKmGUJLBszrw6WTIeP7D92/JucYoozIs4VrBJOU6c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784130416; c=relaxed/simple; bh=Na7db9/2s80znu/9AE5DCwfjSCJNFyIOryOmFE9wqsM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=C9oTt1kgIzPk5dVW01NhmMbFIWcHt43bJwme/pLQGkOcy24dSFXcTDGRFiZXlsoHkAgZkhWfZiC2yUsR2dFZ5kwzCZRCi73q/lMmpS+PwhGirE1Tgv4PY37wS/s2nf8MmExGcH4tnYzywBlpGyjQs7OH1338n/cndw2K/5FkbZs= 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=L2RSk8iT; 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="L2RSk8iT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784130412; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XtAUMyjozqDTITd3GB3tSLmdiU/PUp/kO4z4pdtBy74=; b=L2RSk8iT8TLT/ZoFZIcrrInFw8Y/V8Zk6Nzu9+zFfGCmc5MZZMZRrpjfvPyMwJiNEAVffr 8iqCS8DHGcq9ZGnG3BsoO5NmKBUwnRGMNEr2ii9/SmjYckeVm/TxCfZt5lCMskWry2ZNE+ GRSMVGRQubg+Fl0tgSHug4c2e/LuJiM= 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-81-9AWdsB8KOXSWZy5Ue6FOOA-1; Wed, 15 Jul 2026 11:46:49 -0400 X-MC-Unique: 9AWdsB8KOXSWZy5Ue6FOOA-1 X-Mimecast-MFC-AGG-ID: 9AWdsB8KOXSWZy5Ue6FOOA_1784130407 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 87A1C1955F70; Wed, 15 Jul 2026 15:46:47 +0000 (UTC) Received: from vschneid-thinkpadt14sgen2i.remote.csb (unknown [10.44.32.112]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 326BB1800286; Wed, 15 Jul 2026 15:46:43 +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 v3 3/6] rtla/osnoise: Leverage IPI event filters when tracing a subset of CPUs Date: Wed, 15 Jul 2026 17:45:48 +0200 Message-ID: <20260715154553.2020891-4-vschneid@redhat.com> In-Reply-To: <20260715154553.2020891-1-vschneid@redhat.com> References: <20260715154553.2020891-1-vschneid@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Leverage the kernel event filtering infrastructure to only emit IPI events if they target CPUs that are being traced, as specified by the -c cmdline option. Note that some post-processing is still required for the ipi_send_cpumask event, as the event being emitted means *some* CPUs targeted by that event are monitored, but not all of them - userspace has to recompute that intersection. Signed-off-by: Valentin Schneider --- tools/tracing/rtla/src/osnoise_top.c | 38 ++++++++++++++++++++++++---- 1 file changed, 33 insertions(+), 5 deletions(-) diff --git a/tools/tracing/rtla/src/osnoise_top.c b/tools/tracing/rtla/src/osnoise_top.c index 7b5ae5336cf08..353b435fefcf8 100644 --- a/tools/tracing/rtla/src/osnoise_top.c +++ b/tools/tracing/rtla/src/osnoise_top.c @@ -302,17 +302,13 @@ osnoise_ipi_cpu_handler(struct trace_seq *s, struct tep_record *record, struct tep_event *event, void *context) { struct osnoise_tool *tool; - struct osnoise_params *params; unsigned long long dst_cpu; struct trace_instance *trace = context; tool = container_of(trace, struct osnoise_tool, trace); - params = to_osnoise_params(tool->params); - tep_get_field_val(s, event, "cpu", record, &dst_cpu, 1); - if (CPU_ISSET(dst_cpu, ¶ms->common.monitored_cpus)) - account_ipi(tool, dst_cpu); + account_ipi(tool, dst_cpu); return 0; } @@ -346,6 +342,11 @@ osnoise_ipi_cpumask_handler(struct trace_seq *s, struct tep_record *record, return 0; } + /* + * Despite already filtering for such an intersection, we need to compute + * the intersection here as the @cpumask field may contain non-monitored + * CPUs. + */ CPU_AND(&cpumask_tmp_cpus, event_cpus, ¶ms->common.monitored_cpus); /* @@ -398,6 +399,33 @@ struct osnoise_tool *osnoise_init_top(struct common_params *params) goto out_err; } + /* + * If tracing on a subset of possible CPUs, leverage the kernel filtering + * infrastructure to only generate events on traced CPUs. + */ + if (params->cpus) { + char filter[MAX_PATH]; + + snprintf(filter, ARRAY_SIZE(filter), "cpu & CPUS{%s}\n", params->cpus); + retval = tracefs_event_file_write(tool->trace.inst, + "ipi", "ipi_send_cpu", "filter", + filter); + if (retval < 0) { + err_msg("Could not set ipi_send_cpu CPU filter\n"); + goto out_err; + } + + + snprintf(filter, ARRAY_SIZE(filter), "cpumask & CPUS{%s}\n", params->cpus); + retval = tracefs_event_file_write(tool->trace.inst, + "ipi", "ipi_send_cpumask", "filter", + filter); + if (retval < 0) { + err_msg("Could not set ipi_send_cpumask CPU filter\n"); + goto out_err; + } + } + tep_register_event_handler(tool->trace.tep, -1, "ipi", "ipi_send_cpu", osnoise_ipi_cpu_handler, NULL); -- 2.55.0