From nobody Sun Feb 8 12:36:56 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 494DDEB64DA for ; Tue, 13 Jun 2023 22:08:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235053AbjFMWIc (ORCPT ); Tue, 13 Jun 2023 18:08:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230091AbjFMWI1 (ORCPT ); Tue, 13 Jun 2023 18:08:27 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5E8DD10E6 for ; Tue, 13 Jun 2023 15:08:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id DBD7363B71 for ; Tue, 13 Jun 2023 22:08:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48E4BC433CB; Tue, 13 Jun 2023 22:08:25 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.96) (envelope-from ) id 1q9CBc-000EDc-0c; Tue, 13 Jun 2023 18:08:24 -0400 Message-ID: <20230613220824.008781599@goodmis.org> User-Agent: quilt/0.66 Date: Tue, 13 Jun 2023 18:07:54 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Daniel Bristot de Oliveira , William White , Jonathan Corbet , Juri Lelli Subject: [for-next][PATCH 04/11] rtla: Automatically move rtla to a house-keeping cpu References: <20230613220750.330146797@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Daniel Bristot de Oliveira When the user sets -c try to move rtla out of the , even without an -H option. This is useful to avoid having rtla interfering with the workload. This works by removing from rtla's current affinity. If rtla fails to move itself away it is not that of a problem as this is an automatic measure. Link: https://lkml.kernel.org/r/c54304d90c777310fb85a3e658d1449173759aab.16= 86066600.git.bristot@kernel.org Cc: William White Cc: Jonathan Corbet Tested-by: Juri Lelli Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) --- tools/tracing/rtla/src/osnoise_hist.c | 9 +++++ tools/tracing/rtla/src/osnoise_top.c | 9 +++++ tools/tracing/rtla/src/timerlat_hist.c | 9 +++++ tools/tracing/rtla/src/timerlat_top.c | 9 +++++ tools/tracing/rtla/src/utils.c | 50 ++++++++++++++++++++++++++ tools/tracing/rtla/src/utils.h | 1 + 6 files changed, 87 insertions(+) diff --git a/tools/tracing/rtla/src/osnoise_hist.c b/tools/tracing/rtla/src= /osnoise_hist.c index b616a72d5c0a..dfbcb5ca7ecb 100644 --- a/tools/tracing/rtla/src/osnoise_hist.c +++ b/tools/tracing/rtla/src/osnoise_hist.c @@ -753,6 +753,15 @@ osnoise_hist_apply_config(struct osnoise_tool *tool, s= truct osnoise_hist_params err_msg("Failed to set rtla to the house keeping CPUs\n"); goto out_err; } + } else if (params->cpus) { + /* + * Even if the user do not set a house-keeping CPU, try to + * move rtla to a CPU set different to the one where the user + * set the workload to run. + * + * No need to check results as this is an automatic attempt. + */ + auto_house_keeping(¶ms->monitored_cpus); } =20 return 0; diff --git a/tools/tracing/rtla/src/osnoise_top.c b/tools/tracing/rtla/src/= osnoise_top.c index 0e2f3b216d34..0833537bb2eb 100644 --- a/tools/tracing/rtla/src/osnoise_top.c +++ b/tools/tracing/rtla/src/osnoise_top.c @@ -582,6 +582,15 @@ osnoise_top_apply_config(struct osnoise_tool *tool, st= ruct osnoise_top_params *p err_msg("Failed to set rtla to the house keeping CPUs\n"); goto out_err; } + } else if (params->cpus) { + /* + * Even if the user do not set a house-keeping CPU, try to + * move rtla to a CPU set different to the one where the user + * set the workload to run. + * + * No need to check results as this is an automatic attempt. + */ + auto_house_keeping(¶ms->monitored_cpus); } =20 return 0; diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/sr= c/timerlat_hist.c index 00287e96f22e..1675d54cae81 100644 --- a/tools/tracing/rtla/src/timerlat_hist.c +++ b/tools/tracing/rtla/src/timerlat_hist.c @@ -776,6 +776,15 @@ timerlat_hist_apply_config(struct osnoise_tool *tool, = struct timerlat_hist_param err_msg("Failed to set rtla to the house keeping CPUs\n"); goto out_err; } + } else if (params->cpus) { + /* + * Even if the user do not set a house-keeping CPU, try to + * move rtla to a CPU set different to the one where the user + * set the workload to run. + * + * No need to check results as this is an automatic attempt. + */ + auto_house_keeping(¶ms->monitored_cpus); } =20 return 0; diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src= /timerlat_top.c index 920f2f6ef842..f0c6d9735e2a 100644 --- a/tools/tracing/rtla/src/timerlat_top.c +++ b/tools/tracing/rtla/src/timerlat_top.c @@ -619,6 +619,15 @@ timerlat_top_apply_config(struct osnoise_tool *top, st= ruct timerlat_top_params * err_msg("Failed to set rtla to the house keeping CPUs\n"); goto out_err; } + } else if (params->cpus) { + /* + * Even if the user do not set a house-keeping CPU, try to + * move rtla to a CPU set different to the one where the user + * set the workload to run. + * + * No need to check results as this is an automatic attempt. + */ + auto_house_keeping(¶ms->monitored_cpus); } =20 return 0; diff --git a/tools/tracing/rtla/src/utils.c b/tools/tracing/rtla/src/utils.c index 8f9ad8f01e0f..3e25f0277fb9 100644 --- a/tools/tracing/rtla/src/utils.c +++ b/tools/tracing/rtla/src/utils.c @@ -709,3 +709,53 @@ int set_comm_cgroup(const char *comm_prefix, const cha= r *cgroup) close(cg_fd); return 0; } + +/** + * auto_house_keeping - Automatically move rtla out of measurement threads + * + * Try to move rtla away from the tracer, if possible. + * + * Returns 1 on success, 0 otherwise. + */ +int auto_house_keeping(cpu_set_t *monitored_cpus) +{ + cpu_set_t rtla_cpus, house_keeping_cpus; + int retval; + + /* first get the CPUs in which rtla can actually run. */ + retval =3D sched_getaffinity(getpid(), sizeof(rtla_cpus), &rtla_cpus); + if (retval =3D=3D -1) { + debug_msg("Could not get rtla affinity, rtla might run with the threads!= \n"); + return 0; + } + + /* then check if the existing setup is already good. */ + CPU_AND(&house_keeping_cpus, &rtla_cpus, monitored_cpus); + if (!CPU_COUNT(&house_keeping_cpus)) { + debug_msg("rtla and the monitored CPUs do not share CPUs."); + debug_msg("Skipping auto house-keeping\n"); + return 1; + } + + /* remove the intersection */ + CPU_XOR(&house_keeping_cpus, &rtla_cpus, monitored_cpus); + + /* get only those that rtla can run */ + CPU_AND(&house_keeping_cpus, &house_keeping_cpus, &rtla_cpus); + + /* is there any cpu left? */ + if (!CPU_COUNT(&house_keeping_cpus)) { + debug_msg("Could not find any CPU for auto house-keeping\n"); + return 0; + } + + retval =3D sched_setaffinity(getpid(), sizeof(house_keeping_cpus), &house= _keeping_cpus); + if (retval =3D=3D -1) { + debug_msg("Could not set affinity for auto house-keeping\n"); + return 0; + } + + debug_msg("rtla automatically moved to an auto house-keeping cpu set\n"); + + return 1; +} diff --git a/tools/tracing/rtla/src/utils.h b/tools/tracing/rtla/src/utils.h index 9ab2f0d7bc1c..dec59163cfbc 100644 --- a/tools/tracing/rtla/src/utils.h +++ b/tools/tracing/rtla/src/utils.h @@ -60,6 +60,7 @@ int parse_cpu_set(char *cpu_list, cpu_set_t *set); int set_comm_sched_attr(const char *comm_prefix, struct sched_attr *attr); int set_comm_cgroup(const char *comm_prefix, const char *cgroup); int set_cpu_dma_latency(int32_t latency); +int auto_house_keeping(cpu_set_t *monitored_cpus); =20 #define ns_to_usf(x) (((double)x/1000)) #define ns_to_per(total, part) ((part * 100) / (double)total) --=20 2.39.2