From: Peter Zijlstra <peterz@infradead.org>
To: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Chen Yu <yu.c.chen@intel.com>,
linux-kernel@vger.kernel.org,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Valentin Schneider <vschneid@redhat.com>,
David Vernet <void@manifault.com>,
"Gautham R. Shenoy" <gautham.shenoy@amd.com>,
Swapnil Sapkal <swapnil.sapkal@amd.com>,
Shrikanth Hegde <sshegde@linux.ibm.com>
Subject: Re: [RFC PATCH 0/8] sched/fair: Propagate load balancing stats up the sched domain hierarchy
Date: Mon, 17 Mar 2025 18:25:36 +0100 [thread overview]
Message-ID: <20250317172536.GF6888@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20250313093746.6760-1-kprateek.nayak@amd.com>
On Thu, Mar 13, 2025 at 09:37:38AM +0000, K Prateek Nayak wrote:
> tl;dr
>
> This prototype is currently limited in the sense that it can only reuse
> statistics for busy load balancing. Reusing stats for newidle load
> balancing specifically ran into issues elaborated below.
Right, it makes sense for busy load balance, newidle I think:
> David had proposed SHARED_RUNQ [4] to improve on the shortcomings of
> newidle balance for Meta's production workloads.
we need to look at this again. Something around the EEVDF merge made the
thing unhappy -- if we figure out what and fix it, I think this makes
more sense than trying to optimize the current scheme for newidle.
newidle really is about getting *any* work fast, which is a totally
different game than the regular busy balancing.
Anyway, I'll try and have a look through the patches.
next prev parent reply other threads:[~2025-03-17 17:25 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-13 9:37 [RFC PATCH 0/8] sched/fair: Propagate load balancing stats up the sched domain hierarchy K Prateek Nayak
2025-03-13 9:37 ` [RFC PATCH 1/8] sched/topology: Assign sd_share for all non NUMA sched domains K Prateek Nayak
2025-03-13 9:37 ` [RFC PATCH 2/8] sched/topology: Introduce sg->shared K Prateek Nayak
2025-03-13 9:37 ` [RFC PATCH 3/8] sched/fair: Move "struct sg_lb_stats" and its dependencies to sched.h K Prateek Nayak
2025-03-13 9:37 ` [RFC PATCH 4/8] sched/fair: Move sg_{overloaded,overutilized} calculation to sg_lb_stats K Prateek Nayak
2025-03-13 9:37 ` [RFC PATCH 5/8] sched/topology: Define sg_lb_stats_prop and embed it inside sched_domain_shared K Prateek Nayak
2025-03-13 9:37 ` [RFC PATCH 6/8] sched/fair: Increase probability of lb stats being reused K Prateek Nayak
2025-03-17 18:07 ` Chen, Yu C
2025-03-19 6:51 ` K Prateek Nayak
2025-03-13 9:37 ` [RFC PATCH 7/8] sched/fair: Retrieve cached group stats from sg_lb_stats_prop K Prateek Nayak
2025-03-17 18:04 ` Chen, Yu C
2025-03-19 6:42 ` K Prateek Nayak
2025-03-13 9:37 ` [RFC PATCH 8/8] sched/fair: Update stats for sched_domain using the sched_group stats K Prateek Nayak
2025-03-16 10:29 ` [RFC PATCH 09/08] [ANNOTATE] sched/fair: Stats versioning and invalidation K Prateek Nayak
2025-03-16 10:29 ` [RFC PATCH 10/08] sched/fair: Compute nr_{numa,preferred}_running for non-NUMA domains K Prateek Nayak
2025-03-16 10:29 ` [RFC PATCH 11/08] sched/fair: Move from "last_update" to stats versioning K Prateek Nayak
2025-03-16 10:29 ` [RFC PATCH 12/08] sched/fair: Record the cpu that updated the stats last K Prateek Nayak
2025-03-16 10:29 ` [RFC PATCH 13/08] sched/fair: Invalidate stats once the load balancing instance is done K Prateek Nayak
2025-03-16 10:29 ` [RFC PATCH 14/08] [DEBUG] sched/fair: Add more lb_stats around lb_time and stats reuse K Prateek Nayak
2025-03-16 10:29 ` [RFC PATCH 15/08] [DEBUG] tools/lib/perf: Extend schedstats v17 headers to include the new debug fields K Prateek Nayak
2025-03-17 17:25 ` Peter Zijlstra [this message]
2025-03-17 18:23 ` [RFC PATCH 0/8] sched/fair: Propagate load balancing stats up the sched domain hierarchy Chen, Yu C
2025-03-21 10:04 ` Libo Chen
2025-03-24 3:58 ` K Prateek Nayak
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