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From: Peter Zijlstra <peterz@infradead.org>
To: Changwoo Min <changwoo@igalia.com>
Cc: tj@kernel.org, void@manifault.com, mingo@redhat.com,
	kernel-dev@igalia.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/5] sched_ext: Implement scx_bpf_clock_get_ns()
Date: Mon, 18 Nov 2024 10:44:30 +0100	[thread overview]
Message-ID: <20241118094430.GH39245@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <cd08dc10-1763-415f-b9b9-54c0ebc5e32b@igalia.com>

On Mon, Nov 18, 2024 at 12:48:35AM +0900, Changwoo Min wrote:
> Hello,
> 
> On 24. 11. 17. 04:31, Peter Zijlstra wrote:
> > Have you seen the insides of kernel/sched/clock.c ?
> 
> Of course. :-) It would be super helpful if you could let me know
> specific questions or comments.

Well, mostly I don't understand anything about what you're doing.
Perhaps if you explain what's wrong with the bits we have ?

If you're looking at the scheduler, then rq->clock really should be
sufficient.

If you're looking at rando BPF crud, then what's wrong with
local_clock()?

Also, why are we still caring about systems that have crazy TSC?

  reply	other threads:[~2024-11-18  9:44 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-16 16:01 [PATCH 0/5] sched_ext: Support high-performance monotonically non-decreasing clock Changwoo Min
2024-11-16 16:01 ` [PATCH 1/5] sched_ext: Implement scx_rq_clock_update/stale() Changwoo Min
2024-11-16 16:01 ` [PATCH 2/5] sched_ext: Manage the validity of scx_rq_clock Changwoo Min
2024-11-16 19:32   ` Peter Zijlstra
2024-11-17 15:46     ` Changwoo Min
2024-11-18  9:41       ` Peter Zijlstra
2024-11-19  1:19         ` Changwoo Min
2024-11-19  8:17           ` Peter Zijlstra
2024-11-19 15:57             ` Changwoo Min
2024-11-27  0:41               ` Changwoo Min
2024-11-16 16:01 ` [PATCH 3/5] sched_ext: Implement scx_bpf_clock_get_ns() Changwoo Min
2024-11-16 19:31   ` Peter Zijlstra
2024-11-17 15:48     ` Changwoo Min
2024-11-18  9:44       ` Peter Zijlstra [this message]
2024-11-16 16:01 ` [PATCH 4/5] sched_ext: Add scx_bpf_clock_get_ns() for BPF scheduler Changwoo Min
2024-11-16 16:01 ` [PATCH 5/5] sched_ext: Replace bpf_ktime_get_ns() to scx_bpf_clock_get_ns() Changwoo Min

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