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[72.235.129.167]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-7b764fb53dasm8534450a12.65.2024.08.07.12.26.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Aug 2024 12:26:29 -0700 (PDT) Sender: Tejun Heo Date: Wed, 7 Aug 2024 09:26:28 -1000 From: Tejun Heo To: Phil Auld Cc: torvalds@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, joshdon@google.com, brho@google.com, pjt@google.com, derkling@google.com, haoluo@google.com, dvernet@meta.com, dschatzberg@meta.com, dskarlat@cs.cmu.edu, riel@surriel.com, changwoo@igalia.com, himadrics@inria.fr, memxor@gmail.com, andrea.righi@canonical.com, joel@joelfernandes.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH 09/30] sched_ext: Implement BPF extensible scheduler class Message-ID: References: <20240618212056.2833381-1-tj@kernel.org> <20240618212056.2833381-10-tj@kernel.org> <20240807191004.GB47824@pauld.westford.csb> Precedence: bulk X-Mailing-List: bpf@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: <20240807191004.GB47824@pauld.westford.csb> Hello, Phil. On Wed, Aug 07, 2024 at 03:11:08PM -0400, Phil Auld wrote: > On Tue, Jun 18, 2024 at 11:17:24AM -1000 Tejun Heo wrote: > > Implement a new scheduler class sched_ext (SCX), which allows scheduling > > policies to be implemented as BPF programs to achieve the following: > > > > I looks like this is slated for v6.12 now? That would be good. My initial > experimentation with scx has been positive. Yeap and great to hear. > I just picked one email, not completely randomly. > > > - Both enable and disable paths are a bit complicated. The enable path > > switches all tasks without blocking to avoid issues which can arise from > > partially switched states (e.g. the switching task itself being starved). > > The disable path can't trust the BPF scheduler at all, so it also has to > > guarantee forward progress without blocking. See scx_ops_enable() and > > scx_ops_disable_workfn(). > > I think, from a supportability point of view, there needs to be a pr_info, at least, > in each of these places, enable and disable, with the name of the scx scheduler. It > looks like there is at least a pr_error for when one gets ejected due to misbehavior. > But there needs to be a record of when such is loaded and unloaded. Sure, that's not difficult. Will do so soon. Thanks. -- tejun