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[31.46.246.60]) by smtp.gmail.com with ESMTPSA id fj12-20020a05600c0c8c00b0041409db0349sm12387973wmb.48.2024.03.26.12.15.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Mar 2024 12:15:57 -0700 (PDT) Sender: Ingo Molnar Date: Tue, 26 Mar 2024 20:15:55 +0100 From: Ingo Molnar To: Dietmar Eggemann Cc: Shrikanth Hegde , peterz@infradead.org, vincent.guittot@linaro.org, qyousef@layalina.io, linux-kernel@vger.kernel.org, vschneid@redhat.com, joshdon@google.com, riel@surriel.com Subject: Re: [PATCH] sched/fair: Simplify continue_balancing for newidle Message-ID: References: <20240325153926.274284-1-sshegde@linux.ibm.com> <7e6789d6-1e85-4945-8a7b-02cadc95cfa5@linux.ibm.com> <6c1eed8f-455f-4612-be4e-02876f35e37e@arm.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=us-ascii Content-Disposition: inline In-Reply-To: <6c1eed8f-455f-4612-be4e-02876f35e37e@arm.com> * Dietmar Eggemann wrote: > On 26/03/2024 10:00, Shrikanth Hegde wrote: > > > > On 3/26/24 1:37 PM, Ingo Molnar wrote: > >> > >> * Shrikanth Hegde wrote: > >> > > [...] > > >> Is this actually true? Any change to behavior invalidates such a sentence. > > > > From what i think, code path is same and I don't see any functionality changing. > > Correct me if i am wrong. > > > > Currently, sched_balance_newidle does the same check to bail out as the > > should_we_balance check in case of newidle. i.e > > > > should_we_balance > > if (env->dst_rq->nr_running > 0 || env->dst_rq->ttwu_pending) > > return 0; > > > > sched_balance_newidle > > if (pulled_task || this_rq->nr_running > 0 || > > this_rq->ttwu_pending) > > break; > > } > > LGTM. Commit 792b9f65a568 ("sched: Allow newidle balancing to bail out > of load_balance") (Jun 22) made sure that we leave sched_balance_rq() > (former load_balance()) for CPU_NEWLY_IDLE asap to reduce wakeup latency. > > So IMHO, we can use 'continue_balancing' instead of 'this_rq->nr_running > > 0 || this_rq->ttwu_pending' in sched_balance_newidle() (former > newidle_balance()). > > Reviewed-by: Dietmar Eggemann Thanks for the clarification, applied! Ingo