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From: Peter Zijlstra <peterz@infradead.org>
To: Tejun Heo <tj@kernel.org>
Cc: torvalds@linux-foundation.org, mingo@redhat.com,
	juri.lelli@redhat.com, vincent.guittot@linaro.org,
	dietmar.eggemann@arm.com, rostedt@goodmis.org,
	bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
	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: [PATCHSET v6] sched: Implement BPF extensible scheduler class
Date: Fri, 3 May 2024 10:52:32 +0200	[thread overview]
Message-ID: <20240503085232.GC30852@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <ZjPnb1vdt80FrksA@slm.duckdns.org>

On Thu, May 02, 2024 at 09:20:15AM -1000, Tejun Heo wrote:
> Hello, Peter.
> 
> On Thu, May 02, 2024 at 10:48:00AM +0200, Peter Zijlstra wrote:
> > Can you please put your efforts and the touted Google collaboration in
> > fixing the existing cgroup mess?
> 
> I suppose you're referring to Rik's flattened hierarchy patchset.
> 
>   https://lore.kernel.org/all/20190822021740.15554-1-riel@surriel.com
> 
> Rik spent a lot of time and energy on it and IIRC one of the reasons why it
> didn't get pushed further was the lack of any enthusiasm or support from the
> upstream community.
> 
> We can resurrect the discussion on that patchset but how is that connected
> to sched_ext? 

I'm absolutely not taking any of this until at the very least the cgroup
situation that's been created is solved. And even then, I fundamentally
believe the approach to be detrimental to the scheduler eco-system.
Witness the metric ton of toy schedulers written for it, that's all
effort not put into improving the existing code.

You guys Google/Facebook got us the cgroup thing, Google did a lot of
the work for cpu-cgroup, and now you Facebook say you can't live with it
because it's too expensive. Yes Rik did put a lot of effort into it, but
Google shot it down. What am I to do?

You Google/Facebook are touting collaboration, collaborate on fixing it.
Instead of re-posting this over and over. After all, your main
motivation for starting this was the cpu-cgroup overhead.

From where I'm sitting, you created a problem (cpu-cgroup) and now
you're creating an even bigger problem as a work-around. Very much not
appreciated.



  reply	other threads:[~2024-05-03  8:53 UTC|newest]

Thread overview: 138+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-01 15:09 [PATCHSET v6] sched: Implement BPF extensible scheduler class Tejun Heo
2024-05-01 15:09 ` [PATCH 01/39] cgroup: Implement cgroup_show_cftypes() Tejun Heo
2024-05-01 15:09 ` [PATCH 02/39] sched: Restructure sched_class order sanity checks in sched_init() Tejun Heo
2024-05-01 15:09 ` [PATCH 03/39] sched: Allow sched_cgroup_fork() to fail and introduce sched_cancel_fork() Tejun Heo
2024-05-01 15:09 ` [PATCH 04/39] sched: Add sched_class->reweight_task() Tejun Heo
2024-06-24 10:23   ` Peter Zijlstra
2024-06-24 10:31     ` Peter Zijlstra
2024-06-24 23:59     ` Tejun Heo
2024-06-25  7:29       ` Peter Zijlstra
2024-06-25 23:57         ` Tejun Heo
2024-06-26  1:29           ` [PATCH sched/urgent] sched/fair: set_load_weight() must also call reweight_task() for SCHED_IDLE tasks Tejun Heo
2024-06-26  2:19           ` [PATCH sched_ext/for-6.11] sched_ext: Account for idle policy when setting p->scx.weight in scx_ops_enable_task() Tejun Heo
2024-05-01 15:09 ` [PATCH 05/39] sched: Add sched_class->switching_to() and expose check_class_changing/changed() Tejun Heo
2024-06-24 11:06   ` Peter Zijlstra
2024-06-24 22:18     ` Tejun Heo
2024-06-25  8:16       ` Peter Zijlstra
2024-05-01 15:09 ` [PATCH 06/39] sched: Factor out cgroup weight conversion functions Tejun Heo
2024-05-01 15:09 ` [PATCH 07/39] sched: Expose css_tg() and __setscheduler_prio() Tejun Heo
2024-06-24 11:19   ` Peter Zijlstra
2024-06-24 18:56     ` Tejun Heo
2024-05-01 15:09 ` [PATCH 08/39] sched: Enumerate CPU cgroup file types Tejun Heo
2024-05-01 15:09 ` [PATCH 09/39] sched: Add @reason to sched_class->rq_{on|off}line() Tejun Heo
2024-06-24 11:32   ` Peter Zijlstra
2024-06-24 21:18     ` Tejun Heo
2024-06-25  8:29       ` Peter Zijlstra
2024-06-25 23:41         ` Tejun Heo
2024-06-26  8:23           ` Peter Zijlstra
2024-06-26 18:01             ` Tejun Heo
2024-06-27  1:27               ` [PATCH sched_ext/for-6.11] sched_ext: Disallow loading BPF scheduler if isolcpus= domain isolation is in effect Tejun Heo
2024-05-01 15:09 ` [PATCH 10/39] sched: Factor out update_other_load_avgs() from __update_blocked_others() Tejun Heo
2024-06-24 12:35   ` Peter Zijlstra
2024-06-24 16:15     ` Vincent Guittot
2024-06-24 19:24       ` Tejun Heo
2024-06-25  9:13         ` Vincent Guittot
2024-06-26 20:49           ` Tejun Heo
2024-05-01 15:09 ` [PATCH 11/39] cpufreq_schedutil: Refactor sugov_cpu_is_busy() Tejun Heo
2024-05-01 15:09 ` [PATCH 12/39] sched: Add normal_policy() Tejun Heo
2024-05-01 15:09 ` [PATCH 13/39] sched_ext: Add boilerplate for extensible scheduler class Tejun Heo
2024-05-01 15:09 ` [PATCH 14/39] sched_ext: Implement BPF " Tejun Heo
2024-05-01 15:09 ` [PATCH 15/39] sched_ext: Add scx_simple and scx_example_qmap example schedulers Tejun Heo
2024-05-01 15:09 ` [PATCH 16/39] sched_ext: Add sysrq-S which disables the BPF scheduler Tejun Heo
2024-05-01 15:09 ` [PATCH 17/39] sched_ext: Implement runnable task stall watchdog Tejun Heo
2024-05-01 15:09 ` [PATCH 18/39] sched_ext: Allow BPF schedulers to disallow specific tasks from joining SCHED_EXT Tejun Heo
2024-06-24 12:40   ` Peter Zijlstra
2024-06-24 19:06     ` Tejun Heo
2024-05-01 15:09 ` [PATCH 19/39] sched_ext: Print sched_ext info when dumping stack Tejun Heo
2024-06-24 12:46   ` Peter Zijlstra
2024-06-24 14:25     ` Linus Torvalds
2024-06-24 18:34     ` Tejun Heo
2024-05-01 15:09 ` [PATCH 20/39] sched_ext: Print debug dump after an error exit Tejun Heo
2024-05-01 15:09 ` [PATCH 21/39] tools/sched_ext: Add scx_show_state.py Tejun Heo
2024-05-01 15:09 ` [PATCH 22/39] sched_ext: Implement scx_bpf_kick_cpu() and task preemption support Tejun Heo
2024-05-01 15:09 ` [PATCH 23/39] sched_ext: Add a central scheduler which makes all scheduling decisions on one CPU Tejun Heo
2024-05-01 15:09 ` [PATCH 24/39] sched_ext: Make watchdog handle ops.dispatch() looping stall Tejun Heo
2024-05-01 15:10 ` [PATCH 25/39] sched_ext: Add task state tracking operations Tejun Heo
2024-05-01 15:10 ` [PATCH 26/39] sched_ext: Implement tickless support Tejun Heo
2024-05-01 15:10 ` [PATCH 27/39] sched_ext: Track tasks that are subjects of the in-flight SCX operation Tejun Heo
2024-05-01 15:10 ` [PATCH 28/39] sched_ext: Add cgroup support Tejun Heo
2024-05-01 15:10 ` [PATCH 29/39] sched_ext: Add a cgroup scheduler which uses flattened hierarchy Tejun Heo
2024-05-01 15:10 ` [PATCH 30/39] sched_ext: Implement SCX_KICK_WAIT Tejun Heo
2024-05-01 15:10 ` [PATCH 31/39] sched_ext: Implement sched_ext_ops.cpu_acquire/release() Tejun Heo
2024-05-01 15:10 ` [PATCH 32/39] sched_ext: Implement sched_ext_ops.cpu_online/offline() Tejun Heo
2024-05-01 15:10 ` [PATCH 33/39] sched_ext: Bypass BPF scheduler while PM events are in progress Tejun Heo
2024-05-01 15:10 ` [PATCH 34/39] sched_ext: Implement core-sched support Tejun Heo
2024-05-01 15:10 ` [PATCH 35/39] sched_ext: Add vtime-ordered priority queue to dispatch_q's Tejun Heo
2024-05-01 15:10 ` [PATCH 36/39] sched_ext: Implement DSQ iterator Tejun Heo
2024-05-01 15:10 ` [PATCH 37/39] sched_ext: Add cpuperf support Tejun Heo
2024-05-01 15:10 ` [PATCH 38/39] sched_ext: Documentation: scheduler: Document extensible scheduler class Tejun Heo
2024-05-02  2:24   ` Bagas Sanjaya
2024-05-01 15:10 ` [PATCH 39/39] sched_ext: Add selftests Tejun Heo
2024-05-02  8:48 ` [PATCHSET v6] sched: Implement BPF extensible scheduler class Peter Zijlstra
2024-05-02 19:20   ` Tejun Heo
2024-05-03  8:52     ` Peter Zijlstra [this message]
2024-05-05 23:31       ` Tejun Heo
2024-05-13  8:03         ` Peter Zijlstra
2024-05-13 18:26           ` Steven Rostedt
2024-05-14  0:07             ` Qais Yousef
2024-05-14 21:34               ` David Vernet
2024-05-27 21:25                 ` Qais Yousef
2024-05-28 23:46                   ` Tejun Heo
2024-05-29 22:09                     ` Qais Yousef
2024-05-17  9:58               ` Peter Zijlstra
2024-05-27 20:29                 ` Qais Yousef
2024-05-14 20:22           ` Chris Mason
2024-05-14 22:06           ` Josh Don
2024-05-15 20:41           ` Tejun Heo
2024-05-21  0:19             ` Tejun Heo
2024-05-30 16:49               ` Tejun Heo
2024-05-06 18:47       ` Rik van Riel
2024-05-07 19:33         ` Tejun Heo
2024-05-07 19:47           ` Rik van Riel
2024-05-09  7:38       ` Changwoo Min
2024-05-10 18:24 ` Peter Jung
2024-05-13 20:36 ` Andrea Righi
2024-06-11 21:34 ` Linus Torvalds
2024-06-13 23:38   ` Tejun Heo
2024-06-19 20:56   ` Thomas Gleixner
2024-06-19 22:10     ` Linus Torvalds
2024-06-19 22:27       ` Thomas Gleixner
2024-06-19 22:55         ` Linus Torvalds
2024-06-20  2:35           ` Thomas Gleixner
2024-06-20  5:07             ` Linus Torvalds
2024-06-20 17:11               ` Linus Torvalds
2024-06-20 17:41                 ` Tejun Heo
2024-06-20 22:15                   ` [PATCH sched_ext/for-6.11] sched, sched_ext: Replace scx_next_task_picked() with sched_class->switch_class() Tejun Heo
2024-06-20 22:42                     ` Linus Torvalds
2024-06-21 19:46                       ` Tejun Heo
2024-06-24  9:04                         ` Peter Zijlstra
2024-06-24 18:41                           ` Tejun Heo
2024-06-24  9:02                       ` Peter Zijlstra
2024-06-21 19:52                     ` Tejun Heo
2024-06-24  8:59                     ` Peter Zijlstra
2024-06-24 21:01                       ` Tejun Heo
2024-06-25  7:49                         ` Peter Zijlstra
2024-06-25 23:30                           ` Tejun Heo
2024-06-26  8:28                             ` Peter Zijlstra
2024-06-26 17:56                               ` Tejun Heo
2024-06-20 18:47               ` [PATCHSET v6] sched: Implement BPF extensible scheduler class Thomas Gleixner
2024-06-20 19:20                 ` Linus Torvalds
2024-06-21  9:35                   ` Thomas Gleixner
2024-06-21 16:34                     ` Linus Torvalds
2024-06-23  2:00                       ` Tejun Heo
2024-06-23 10:31                       ` Thomas Gleixner
2024-06-23 10:33                       ` Thomas Gleixner
2024-06-24 14:23                         ` Jason Gunthorpe
2024-06-20 19:58                 ` Tejun Heo
2024-06-24  9:34                   ` Peter Zijlstra
2024-06-24 20:17                     ` Tejun Heo
2024-06-24 20:51                       ` [PATCH sched_ext/for-6.11] sched, sched_ext: Simplify dl_prio() case handling in sched_fork() Tejun Heo
2024-06-20 19:35             ` [PATCHSET v6] sched: Implement BPF extensible scheduler class Tejun Heo
2024-06-21 10:46               ` Thomas Gleixner
2024-06-21 21:14                 ` Chris Mason
2024-06-23  8:14                   ` Thomas Gleixner
2024-06-24 16:42                     ` Chris Mason
2024-06-24 18:11                       ` Tejun Heo
2024-06-24 22:01                         ` Peter Oskolkov
2024-06-24 22:17                     ` David Vernet
2024-06-24 21:54             ` Peter Oskolkov

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