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From: Peter Zijlstra <peterz@infradead.org>
To: Josh Don <joshdon@google.com>
Cc: mingo@kernel.org, vincent.guittot@linaro.org,
	linux-kernel@vger.kernel.org, juri.lelli@redhat.com,
	dietmar.eggemann@arm.com, rostedt@goodmis.org,
	bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
	corbet@lwn.net, qyousef@layalina.io, chris.hyser@oracle.com,
	patrick.bellasi@matbug.net, pjt@google.com, pavel@ucw.cz,
	qperret@google.com, tim.c.chen@linux.intel.com, timj@gnu.org,
	kprateek.nayak@amd.com, yu.c.chen@intel.com,
	youssefesmat@chromium.org, joel@joelfernandes.org, efault@gmx.de
Subject: Re: [PATCH 04/17] sched/fair: Add avg_vruntime
Date: Wed, 29 Mar 2023 09:50:51 +0200	[thread overview]
Message-ID: <20230329075051.GJ4253@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CABk29Nt-9MufWcyxr8=ghHDj_kUj21vkEw=4X10NpXncxN32uQ@mail.gmail.com>

On Tue, Mar 28, 2023 at 04:57:49PM -0700, Josh Don wrote:
> On Tue, Mar 28, 2023 at 4:06 AM Peter Zijlstra <peterz@infradead.org> wrote:
> [...]
> > +/*
> > + * Compute virtual time from the per-task service numbers:
> > + *
> > + * Fair schedulers conserve lag: \Sum lag_i = 0
> > + *
> > + * lag_i = S - s_i = w_i * (V - v_i)
> > + *
> > + * \Sum lag_i = 0 -> \Sum w_i * (V - v_i) = V * \Sum w_i - \Sum w_i * v_i = 0
> 
> Small note: I think it would be helpful to label these symbols
> somewhere :) Weight  and vruntime are fairly obvious, but I don't
> think 'S' and 'V' are as clear. Are these non-virtual ideal service
> time, and average vruntime, respectively?

Yep, they are. I'll see what I can do with the comments.

  reply	other threads:[~2023-03-29  7:52 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-28  9:26 [PATCH 00/17] sched: EEVDF using latency-nice Peter Zijlstra
2023-03-28  9:26 ` [PATCH 01/17] sched: Introduce latency-nice as a per-task attribute Peter Zijlstra
2023-03-28  9:26 ` [PATCH 02/17] sched/fair: Add latency_offset Peter Zijlstra
2023-03-28  9:26 ` [PATCH 03/17] sched/fair: Add sched group latency support Peter Zijlstra
2023-03-28  9:26 ` [PATCH 04/17] sched/fair: Add avg_vruntime Peter Zijlstra
2023-03-28 23:57   ` Josh Don
2023-03-29  7:50     ` Peter Zijlstra [this message]
2023-04-05 19:13       ` Peter Zijlstra
2023-03-28  9:26 ` [PATCH 05/17] sched/fair: Remove START_DEBIT Peter Zijlstra
2023-03-28  9:26 ` [PATCH 06/17] sched/fair: Add lag based placement Peter Zijlstra
2023-04-03  9:18   ` Chen Yu
2023-04-05  9:47     ` Peter Zijlstra
2023-04-06  3:03       ` Chen Yu
2023-04-13 15:42       ` Chen Yu
2023-04-13 15:55         ` Chen Yu
2023-03-28  9:26 ` [PATCH 07/17] rbtree: Add rb_add_augmented_cached() helper Peter Zijlstra
2023-03-28  9:26 ` [PATCH 08/17] sched/fair: Implement an EEVDF like policy Peter Zijlstra
2023-03-29  1:26   ` Josh Don
2023-03-29  8:02     ` Peter Zijlstra
2023-03-29  8:06     ` Peter Zijlstra
2023-03-29  8:22       ` Peter Zijlstra
2023-03-29 18:48         ` Josh Don
2023-03-29  8:12     ` Peter Zijlstra
2023-03-29 18:54       ` Josh Don
2023-03-29  8:18     ` Peter Zijlstra
2023-03-29 14:35   ` Vincent Guittot
2023-03-30  8:01     ` Peter Zijlstra
2023-03-30 17:05       ` Vincent Guittot
2023-04-04 12:00         ` Peter Zijlstra
2023-03-28  9:26 ` [PATCH 09/17] sched: Commit to lag based placement Peter Zijlstra
2023-03-28  9:26 ` [PATCH 10/17] sched/smp: Use lag to simplify cross-runqueue placement Peter Zijlstra
2023-03-28  9:26 ` [PATCH 11/17] sched: Commit to EEVDF Peter Zijlstra
2023-03-28  9:26 ` [PATCH 12/17] sched/debug: Rename min_granularity to base_slice Peter Zijlstra
2023-03-28  9:26 ` [PATCH 13/17] sched: Merge latency_offset into slice Peter Zijlstra
2023-03-28  9:26 ` [PATCH 14/17] sched/eevdf: Better handle mixed slice length Peter Zijlstra
2023-03-31 15:26   ` Vincent Guittot
2023-04-04  9:29     ` Peter Zijlstra
2023-04-04 13:50       ` Joel Fernandes
2023-04-05  5:41         ` Mike Galbraith
2023-04-05  8:35         ` Peter Zijlstra
2023-04-05 20:05           ` Joel Fernandes
2023-04-14 11:18             ` Phil Auld
2023-04-16  5:10               ` Joel Fernandes
     [not found]   ` <20230401232355.336-1-hdanton@sina.com>
2023-04-02  2:40     ` Mike Galbraith
2023-03-28  9:26 ` [PATCH 15/17] [RFC] sched/eevdf: Sleeper bonus Peter Zijlstra
2023-03-29  9:10   ` Mike Galbraith
2023-03-28  9:26 ` [PATCH 16/17] [RFC] sched/eevdf: Minimal vavg option Peter Zijlstra
2023-03-28  9:26 ` [PATCH 17/17] [DEBUG] sched/eevdf: Debug / validation crud Peter Zijlstra
2023-04-03  7:42 ` [PATCH 00/17] sched: EEVDF using latency-nice Shrikanth Hegde
2023-04-10  3:13 ` David Vernet
2023-04-11  2:09   ` David Vernet
     [not found] ` <20230410082307.1327-1-hdanton@sina.com>
2023-04-11 10:15   ` Mike Galbraith
     [not found]   ` <20230411133333.1790-1-hdanton@sina.com>
2023-04-11 14:56     ` Mike Galbraith
     [not found]     ` <20230412025042.1413-1-hdanton@sina.com>
2023-04-12  4:05       ` Mike Galbraith
2023-04-25 12:32 ` Phil Auld

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