From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7383FC433E1 for ; Thu, 18 Jun 2020 22:41:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4DACC206F1 for ; Thu, 18 Jun 2020 22:41:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592520061; bh=mSTGr0z1t50V+4PETgkloUEYdLRH7d9JFYjF022gv9c=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=cpFCasbPib47zopsJvt3tRJ4iAYOjdnrH3q75yqdaP3XuhtpVuf41H4w3m3suiWvG uzT4pMjHmhzTk7mTxqIgbi4GyVCcu/d6JQ7naAJXZi0AzIX/Sz+AomTv1GjrqXyJMj y+Qb+X+YQqD8Cfm3csHIeR3dTNipF8tqBA5EXhrE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730163AbgFRWlA (ORCPT ); Thu, 18 Jun 2020 18:41:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:55954 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726835AbgFRWk7 (ORCPT ); Thu, 18 Jun 2020 18:40:59 -0400 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9BF7C206E2; Thu, 18 Jun 2020 22:40:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592520058; bh=mSTGr0z1t50V+4PETgkloUEYdLRH7d9JFYjF022gv9c=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=XK29KKgqdhmppO7VOvmr16E5m0h0Kc/cOA9G/gfzf0jRQVvvmoNhP664RVYenDmNC 2KuGOE9ZMZyPDSiUdl8sqF9R1BoYSes4VAxk9Ss92yVCI8DuDuWEhcl/injAPw/PyP 5fHWk9sK6Rum4ecg+o/x/XkvxbqUJTWOMzY67btQ= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 801DE352264E; Thu, 18 Jun 2020 15:40:58 -0700 (PDT) Date: Thu, 18 Jun 2020 15:40:58 -0700 From: "Paul E. McKenney" To: "Joel Fernandes (Google)" Cc: linux-kernel@vger.kernel.org, Davidlohr Bueso , Ingo Molnar , Josh Triplett , Lai Jiangshan , Marco Elver , Mathieu Desnoyers , rcu@vger.kernel.org, Steven Rostedt , "Uladzislau Rezki (Sony)" Subject: Re: [PATCH 6/7] rcutorture: Add support to get the number of wakeups of main GP kthread Message-ID: <20200618224058.GD2723@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200618202955.4024-1-joel@joelfernandes.org> <20200618202955.4024-6-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200618202955.4024-6-joel@joelfernandes.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 18, 2020 at 04:29:54PM -0400, Joel Fernandes (Google) wrote: > This is useful to check for any improvements or degradation related to > number of GP kthread wakeups during testing. > > Signed-off-by: Joel Fernandes (Google) This was a good way to collect the data for your testing, but we can expect rcutorture to only do so much. ;-) Thanx, Paul > --- > kernel/rcu/Kconfig.debug | 1 + > kernel/rcu/rcu.h | 2 ++ > kernel/rcu/rcutorture.c | 23 ++++++++++++++++++++++- > kernel/rcu/tree.c | 7 +++++++ > 4 files changed, 32 insertions(+), 1 deletion(-) > > diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug > index 3cf6132a4bb9f..3323e3378af5a 100644 > --- a/kernel/rcu/Kconfig.debug > +++ b/kernel/rcu/Kconfig.debug > @@ -50,6 +50,7 @@ config RCU_TORTURE_TEST > select TASKS_RCU > select TASKS_RUDE_RCU > select TASKS_TRACE_RCU > + select SCHEDSTATS > default n > help > This option provides a kernel module that runs torture tests > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h > index cf66a3ccd7573..7e867e81d9738 100644 > --- a/kernel/rcu/rcu.h > +++ b/kernel/rcu/rcu.h > @@ -511,6 +511,7 @@ srcu_batches_completed(struct srcu_struct *sp) { return 0; } > static inline void rcu_force_quiescent_state(void) { } > static inline void show_rcu_gp_kthreads(void) { } > static inline int rcu_get_gp_kthreads_prio(void) { return 0; } > +static inline struct task_struct *rcu_get_main_gp_kthread(void) { return 0; } > static inline void rcu_fwd_progress_check(unsigned long j) { } > #else /* #ifdef CONFIG_TINY_RCU */ > bool rcu_dynticks_zero_in_eqs(int cpu, int *vp); > @@ -519,6 +520,7 @@ unsigned long rcu_exp_batches_completed(void); > unsigned long srcu_batches_completed(struct srcu_struct *sp); > void show_rcu_gp_kthreads(void); > int rcu_get_gp_kthreads_prio(void); > +struct task_struct *rcu_get_main_gp_kthread(void); > void rcu_fwd_progress_check(unsigned long j); > void rcu_force_quiescent_state(void); > extern struct workqueue_struct *rcu_gp_wq; > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c > index d0d265304d147..959a1f84d6904 100644 > --- a/kernel/rcu/rcutorture.c > +++ b/kernel/rcu/rcutorture.c > @@ -23,6 +23,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -460,9 +461,29 @@ static void rcu_sync_torture_init(void) > INIT_LIST_HEAD(&rcu_torture_removed); > } > > +unsigned long rcu_gp_nr_wakeups; > + > +static void rcu_flavor_init(void) > +{ > + rcu_sync_torture_init(); > + > + /* Make sure schedstat is enabled for GP thread wakeup count. */ > + force_schedstat_enabled(); > + rcu_gp_nr_wakeups = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups; > +} > + > +static void rcu_flavor_cleanup(void) > +{ > + unsigned long now_nr = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups; > + > + pr_alert("End-test: Cleanup: Total GP-kthread wakeups: %lu\n", > + now_nr - rcu_gp_nr_wakeups); > +} > + > static struct rcu_torture_ops rcu_ops = { > .ttype = RCU_FLAVOR, > - .init = rcu_sync_torture_init, > + .init = rcu_flavor_init, > + .cleanup = rcu_flavor_cleanup, > .readlock = rcu_torture_read_lock, > .read_delay = rcu_read_delay, > .readunlock = rcu_torture_read_unlock, > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index c3bae7a83d792..a3a175feb310a 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -175,6 +175,13 @@ int rcu_get_gp_kthreads_prio(void) > } > EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio); > > +/* Retrieve RCU's main GP kthread task_struct */ > +struct task_struct *rcu_get_main_gp_kthread(void) > +{ > + return rcu_state.gp_kthread; > +} > +EXPORT_SYMBOL_GPL(rcu_get_main_gp_kthread); > + > /* > * Number of grace periods between delays, normalized by the duration of > * the delay. The longer the delay, the more the grace periods between > -- > 2.27.0.111.gc72c7da667-goog >