mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Shrikanth Hegde <sshegde@linux.ibm.com>
Cc: Thomas Gleixner <tglx@kernel.org>,
	linux-kernel@vger.kernel.org, Juri Lelli <juri.lelli@redhat.com>,
	x86@kernel.org, linux-tip-commits@vger.kernel.org
Subject: Re: [tip: sched/hrtick] sched/eevdf: Fix HRTICK duration
Date: Fri, 20 Mar 2026 16:38:23 +0100	[thread overview]
Message-ID: <20260320153823.GN2872@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <2fcb640d-a7b7-43dd-b057-50d90d4ca0db@linux.ibm.com>

On Fri, Mar 20, 2026 at 08:29:11PM +0530, Shrikanth Hegde wrote:

> > +	/*
> > +	 * Correct for instantaneous load of other classes.
> > +	 */
> > +	util += cpu_util_irq(rq);
> > +	if (util && util < 1024) {
> > +		scale *= 1024;
> > +		scale /= (1024 - util);
> > +	}
> 
> Comments/Changelog says other classes.
> 
> Then why not consider cpu_util_dl, cpu_util_rq too?
> Is there a reason why these are not taken into calculations?

Damn, forgot to fix that comment.

So yes, it used to correct for those, but then I realized that the
hrtick is strictly for current. So running RT/DL tasks means current is
different.

The only thing that can actually interrupt current and soak time are
interrupts.

Does that make sense?

  reply	other threads:[~2026-03-20 15:38 UTC|newest]

Thread overview: 130+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-24 16:35 [patch 00/48] hrtimer,sched: General optimizations and hrtick enablement Thomas Gleixner
2026-02-24 16:35 ` [patch 01/48] sched/eevdf: Fix HRTICK duration Thomas Gleixner
2026-02-28 15:37   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-03-20 14:59     ` Shrikanth Hegde
2026-03-20 15:38       ` Peter Zijlstra [this message]
2026-03-20 15:40         ` Shrikanth Hegde
2026-02-24 16:35 ` [patch 02/48] sched/fair: Simplify hrtick_update() Thomas Gleixner
2026-02-28 15:37   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra (Intel)
2026-02-24 16:35 ` [patch 03/48] sched/fair: Make hrtick resched hard Thomas Gleixner
2026-02-28 15:37   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra (Intel)
2026-02-24 16:35 ` [patch 04/48] sched: Avoid ktime_get() indirection Thomas Gleixner
2026-02-28 15:37   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:35 ` [patch 05/48] hrtimer: Avoid pointless reprogramming in __hrtimer_start_range_ns() Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-02-24 16:35 ` [patch 06/48] hrtimer: Provide a static branch based hrtimer_hres_enabled() Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:35 ` [patch 07/48] sched: Use hrtimer_highres_enabled() Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:35 ` [patch 08/48] sched: Optimize hrtimer handling Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:35 ` [patch 09/48] sched/hrtick: Avoid tiny hrtick rearms Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:36 ` [patch 10/48] hrtimer: Provide LAZY_REARM mode Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-02-24 16:36 ` [patch 11/48] sched/hrtick: Mark hrtick timer LAZY_REARM Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-02-24 16:36 ` [patch 12/48] tick/sched: Avoid hrtimer_cancel/start() sequence Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:36 ` [patch 13/48] clockevents: Remove redundant CLOCK_EVT_FEAT_KTIME Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:36 ` [patch 14/48] timekeeping: Allow inlining clocksource::read() Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:36 ` [patch 15/48] x86: Inline TSC reads in timekeeping Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:36 ` [patch 16/48] x86/apic: Remove pointless fence in lapic_next_deadline() Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:36 ` [patch 17/48] x86/apic: Avoid the PVOPS indirection for the TSC deadline timer Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-07-10 13:25   ` [patch 17/48] " Artem Bityutskiy
2026-07-10 14:12     ` Juergen Gross
2026-02-24 16:36 ` [patch 18/48] timekeeping: Provide infrastructure for coupled clockevents Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:36 ` [patch 19/48] clockevents: Provide support for clocksource coupled comparators Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-03-03 18:44   ` [patch 19/48] " Michael Kelley
2026-03-03 19:14     ` Peter Zijlstra
2026-03-23  4:24     ` Michael Kelley
2026-03-23 21:36       ` Thomas Gleixner
2026-03-24  0:22         ` mhklkml
2026-03-24  3:37           ` Michael Kelley
2026-03-24 17:24             ` Thomas Gleixner
2026-03-24 17:34               ` Peter Zijlstra
2026-02-24 16:36 ` [patch 20/48] x86/apic: Enable TSC coupled programming mode Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-03-03  1:29   ` [patch 20/48] " Nathan Chancellor
2026-03-03 14:37     ` Thomas Gleixner
2026-03-03 14:45       ` Thomas Gleixner
2026-03-03 17:38       ` Nathan Chancellor
2026-03-03 20:21         ` Thomas Gleixner
2026-03-03 21:30           ` Nathan Chancellor
2026-03-04 18:40             ` Thomas Gleixner
2026-03-04 18:49               ` [patch 20/48] clocksource: Update clocksource::freq_khz on registration Thomas Gleixner
2026-03-04 19:10                 ` Borislav Petkov
2026-03-04 22:57                 ` Nathan Chancellor
2026-03-05 16:47                 ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-03-03 21:56         ` [PATCH] Subject: timekeeping: Initialize the coupled clocksource conversion completely Thomas Gleixner
2026-03-03 23:16           ` John Stultz
2026-03-05 16:47           ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:36 ` [patch 21/48] hrtimer: Add debug object init assertion Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:36 ` [patch 22/48] hrtimer: Reduce trace noise in hrtimer_start() Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 23/48] hrtimer: Use guards where appropriate Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 24/48] hrtimer: Cleanup coding style and comments Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 25/48] hrtimer: Evaluate timer expiry only once Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 26/48] hrtimer: Replace the bitfield in hrtimer_cpu_base Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 27/48] hrtimer: Convert state and properties to boolean Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 28/48] hrtimer: Optimize for local timers Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 29/48] hrtimer: Use NOHZ information for locality Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 30/48] hrtimer: Separate remove/enqueue handling for local timers Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 31/48] hrtimer: Add hrtimer_rearm tracepoint Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 32/48] hrtimer: Re-arrange hrtimer_interrupt() Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-02-24 16:37 ` [patch 33/48] hrtimer: Rename hrtimer_cpu_base::in_hrtirq to deferred_rearm Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:37 ` [patch 34/48] hrtimer: Prepare stubs for deferred rearming Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-02-24 16:38 ` [patch 35/48] entry: Prepare for deferred hrtimer rearming Thomas Gleixner
2026-02-27 15:57   ` Christian Loehle
2026-02-27 16:25     ` Peter Zijlstra
2026-02-27 16:32       ` Christian Loehle
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-02-24 16:38 ` [patch 36/48] softirq: " Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-02-24 16:38 ` [patch 37/48] sched/core: " Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-02-24 16:38 ` [patch 38/48] hrtimer: Push reprogramming timers into the interrupt return path Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-02-24 16:38 ` [patch 39/48] hrtimer: Avoid re-evaluation when nothing changed Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:38 ` [patch 40/48] hrtimer: Keep track of first expiring timer per clock base Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:38 ` [patch 41/48] hrtimer: Rework next event evaluation Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:38 ` [patch 42/48] hrtimer: Simplify run_hrtimer_queues() Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:38 ` [patch 43/48] hrtimer: Optimize for_each_active_base() Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:38 ` [patch 44/48] rbtree: Provide rbtree with links Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:38 ` [patch 45/48] timerqueue: Provide linked timerqueue Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:38 ` [patch 46/48] hrtimer: Use " Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:39 ` [patch 47/48] hrtimer: Try to modify timers in place Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Thomas Gleixner
2026-02-24 16:39 ` [patch 48/48] sched: Default enable HRTICK when deferred rearming is enabled Thomas Gleixner
2026-02-28 15:36   ` [tip: sched/hrtick] " tip-bot2 for Peter Zijlstra
2026-02-25 15:25 ` [patch 00/48] hrtimer,sched: General optimizations and hrtick enablement Peter Zijlstra
2026-02-25 16:02   ` Thomas Gleixner
2026-03-04 15:59 ` Christian Loehle

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260320153823.GN2872@noisy.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=juri.lelli@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tip-commits@vger.kernel.org \
    --cc=sshegde@linux.ibm.com \
    --cc=tglx@kernel.org \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

Powered by JetHome