From nobody Sun Feb 8 22:06:40 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF489EB64DB for ; Thu, 15 Jun 2023 07:01:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239987AbjFOHBl (ORCPT ); Thu, 15 Jun 2023 03:01:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33476 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244490AbjFOHBW (ORCPT ); Thu, 15 Jun 2023 03:01:22 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 91AFB1720 for ; Thu, 15 Jun 2023 00:00:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1686812451; 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=rZl5IePXwMxAc+yncc6R0RiTzMx0XP4ndlclonASOGI=; b=KozAFdaiE/+cDXu6R5WCaZ49HZmR1M8ePvTpoAPU21W9tT1ir74mlpMRYwrE+6h51yuOP/ Ff3lyeKvFu3EY3Fsdi21BO2WtID/II9mbjfKQQnzVMdR8yFDVPWpd8FQ8EpwTpuPZ+pOv0 Hz+k2ou7YNgUtb1+VEkKffW/llCRuX4= Received: from mail-oa1-f70.google.com (mail-oa1-f70.google.com [209.85.160.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-249-_iXHRncOODeo98XF-K2tbA-1; Thu, 15 Jun 2023 03:00:49 -0400 X-MC-Unique: _iXHRncOODeo98XF-K2tbA-1 Received: by mail-oa1-f70.google.com with SMTP id 586e51a60fabf-1a36fa3850dso4581533fac.0 for ; Thu, 15 Jun 2023 00:00:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686812448; x=1689404448; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=rZl5IePXwMxAc+yncc6R0RiTzMx0XP4ndlclonASOGI=; b=SUM4sfFcGvzNne13U9yzViB2bNHhAeHmmABM+p2vp2yDQzvG37ECmt0XMqqEF84r7R WgVRXdQAEaDRcKcO1ZqP5kZPM5gUdskZL+5dSWF8P1ynWuCtBXSkOw+ZLh0ZMosJswzn LGJVsWQGKZCUS75X+Oq52GgxZ0TiSOCOllIhqIZTc6UocR55nJnRhHJ/o14nk7IylYbH vDpWo1ZkAljeHYKDBuULvGh8ljr7S/JM2Uh68y3CzDsGTPGinhQV/Ot3wrS25QevXUt4 fAzKx4F0Pj3Vne9TI1x/b1EISZ+21hLncPzSF4Y+oe1ZyVlroPMqEIHRxvyE7AqeunoX OM+A== X-Gm-Message-State: AC+VfDyOfcNX4KnOstLBtRr9YJlfWn+VsqX5Yvxz3GcDvA8CyIkYJDWG 1xksuUkoi49qHFFKimx37qc0ud1n3tj5KtmjsivFKZPextpn/8VDfyYBOpAX2yFu0Ey4GslGvov /wcORcB8Cn+pBjgLIJJqWtBhG X-Received: by 2002:a05:6870:e896:b0:19f:6fae:d5fc with SMTP id q22-20020a056870e89600b0019f6faed5fcmr10541232oan.33.1686812448502; Thu, 15 Jun 2023 00:00:48 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ4RTn4EVzEzJIlR5WDuNxNcCA8RtViRGRXrf6wQXuxD0HoRgO8I/0CdFEYSCfLpGO8E99u/Bg== X-Received: by 2002:a05:6870:e896:b0:19f:6fae:d5fc with SMTP id q22-20020a056870e89600b0019f6faed5fcmr10541218oan.33.1686812448256; Thu, 15 Jun 2023 00:00:48 -0700 (PDT) Received: from localhost.localdomain ([2804:1b3:a800:60ac:48e:4eb0:11b4:f1e8]) by smtp.gmail.com with ESMTPSA id d4-20020a0568301b6400b006b2b51fd2ebsm6472317ote.81.2023.06.15.00.00.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Jun 2023 00:00:47 -0700 (PDT) From: Leonardo Bras To: Steven Rostedt , Masami Hiramatsu , Leonardo Bras , Peter Zijlstra , "Paul E. McKenney" , Juergen Gross , Valentin Schneider , Yury Norov , Sebastian Andrzej Siewior Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [RFC PATCH v5 2/2] trace,smp: Add tracepoints for scheduling remotelly called functions Date: Thu, 15 Jun 2023 03:59:47 -0300 Message-ID: <20230615065944.188876-7-leobras@redhat.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230615065944.188876-3-leobras@redhat.com> References: <20230615065944.188876-3-leobras@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add a tracepoint for when a CSD is queued to a remote CPU's call_single_queue. This allows finding exactly which CPU queued a given CSD when looking at a csd_function_{entry,exit} event, and also enables us to accurately measure IPI delivery time with e.g. a synthetic event: $ echo 'hist:keys=3Dcpu,csd.hex:ts=3Dcommon_timestamp.usecs' >\ /sys/kernel/tracing/events/smp/csd_queue_cpu/trigger $ echo 'csd_latency unsigned int dst_cpu; unsigned long csd; u64 time' >\ /sys/kernel/tracing/synthetic_events $ echo \ 'hist:keys=3Dcommon_cpu,csd.hex:'\ 'time=3Dcommon_timestamp.usecs-$ts:'\ 'onmatch(smp.csd_queue_cpu).trace(csd_latency,common_cpu,csd,$time)' >\ /sys/kernel/tracing/events/smp/csd_function_entry/trigger $ trace-cmd record -e 'synthetic:csd_latency' hackbench $ trace-cmd report <...>-467 [001] 21.824263: csd_queue_cpu: cpu=3D0 callsite=3D= try_to_wake_up+0x2ea func=3Dsched_ttwu_pending csd=3D0xffff8880076148b8 <...>-467 [001] 21.824280: ipi_send_cpu: cpu=3D0 callsite=3D= try_to_wake_up+0x2ea callback=3Dgeneric_smp_call_function_single_interrupt+= 0x0 <...>-489 [000] 21.824299: csd_function_entry: func=3Dsched_ttwu_p= ending csd=3D0xffff8880076148b8 <...>-489 [000] 21.824320: csd_latency: dst_cpu=3D0, csd=3D= 18446612682193848504, time=3D36 Suggested-by: Valentin Schneider Signed-off-by: Leonardo Bras --- include/trace/events/csd.h | 27 +++++++++++++++++++++++++++ kernel/smp.c | 16 +++++----------- 2 files changed, 32 insertions(+), 11 deletions(-) diff --git a/include/trace/events/csd.h b/include/trace/events/csd.h index af1df5200ae6..67e9d01f80c2 100644 --- a/include/trace/events/csd.h +++ b/include/trace/events/csd.h @@ -7,6 +7,33 @@ =20 #include =20 +TRACE_EVENT(csd_queue_cpu, + + TP_PROTO(const unsigned int cpu, + unsigned long callsite, + smp_call_func_t func, + struct __call_single_data *csd), + + TP_ARGS(cpu, callsite, func, csd), + + TP_STRUCT__entry( + __field(unsigned int, cpu) + __field(void *, callsite) + __field(void *, func) + __field(void *, csd) + ), + + TP_fast_assign( + __entry->cpu =3D cpu; + __entry->callsite =3D (void *)callsite; + __entry->func =3D func; + __entry->csd =3D csd; + ), + + TP_printk("cpu=3D%u callsite=3D%pS func=3D%ps csd=3D%p", + __entry->cpu, __entry->callsite, __entry->func, __entry->csd) + ); + /* * Tracepoints for a function which is called as an effect of smp_call_fun= ction.* */ diff --git a/kernel/smp.c b/kernel/smp.c index 7199b5a22043..692dbb400701 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -340,7 +340,7 @@ void __smp_call_single_queue(int cpu, struct llist_node= *node) * even if we haven't sent the smp_call IPI yet (e.g. the stopper * executes migration_cpu_stop() on the remote CPU). */ - if (trace_ipi_send_cpu_enabled()) { + if (trace_csd_queue_cpu_enabled()) { call_single_data_t *csd; smp_call_func_t func; =20 @@ -348,7 +348,7 @@ void __smp_call_single_queue(int cpu, struct llist_node= *node) func =3D CSD_TYPE(csd) =3D=3D CSD_TYPE_TTWU ? sched_ttwu_pending : csd->func; =20 - trace_ipi_send_cpu(cpu, _RET_IP_, func); + trace_csd_queue_cpu(cpu, _RET_IP_, func, csd); } =20 /* @@ -741,7 +741,7 @@ static void smp_call_function_many_cond(const struct cp= umask *mask, int cpu, last_cpu, this_cpu =3D smp_processor_id(); struct call_function_data *cfd; bool wait =3D scf_flags & SCF_WAIT; - int nr_cpus =3D 0, nr_queued =3D 0; + int nr_cpus =3D 0; bool run_remote =3D false; bool run_local =3D false; =20 @@ -799,21 +799,15 @@ static void smp_call_function_many_cond(const struct = cpumask *mask, csd->node.src =3D smp_processor_id(); csd->node.dst =3D cpu; #endif + trace_csd_queue_cpu(cpu, _RET_IP_, func, csd); + if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) { __cpumask_set_cpu(cpu, cfd->cpumask_ipi); nr_cpus++; last_cpu =3D cpu; } - nr_queued++; } =20 - /* - * Trace each smp_function_call_*() as an IPI, actual IPIs - * will be traced with func=3D=3Dgeneric_smp_call_function_single_ipi(). - */ - if (nr_queued) - trace_ipi_send_cpumask(cfd->cpumask, _RET_IP_, func); - /* * Choose the most efficient way to send an IPI. Note that the * number of CPUs might be zero due to concurrent changes to the --=20 2.41.0