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From: Peter Oskolkov <posk@google.com>
To: Andrei Vagin <avagin@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-api <linux-api@vger.kernel.org>,
	Paul Turner <pjt@google.com>, Ben Segall <bsegall@google.com>,
	Peter Oskolkov <posk@posk.io>,
	Joel Fernandes <joel@joelfernandes.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jim Newsome <jnewsome@torproject.org>
Subject: Re: [RFC PATCH v0.1 0/9] UMCG early preview/RFC patchset
Date: Fri, 21 May 2021 12:13:55 -0700	[thread overview]
Message-ID: <CAPNVh5d54HNYqVSGG==ozA7YjGdmkisg2M+wsYmdgGx2-p3Oog@mail.gmail.com> (raw)
In-Reply-To: <CAEWA0a72SvpcuN4ov=98T3uWtExPCr7BQePOgjkqD1ofWKEASw@mail.gmail.com>

On Fri, May 21, 2021 at 11:44 AM Andrei Vagin <avagin@google.com> wrote:
>
>
>
> On Thu, May 20, 2021 at 11:36 AM Peter Oskolkov <posk@google.com> wrote:
>>
>> As indicated earlier in the FUTEX_SWAP patchset:
>>
>> https://lore.kernel.org/lkml/20200722234538.166697-1-posk@posk.io/
>
>
> Hi Peter,
>
> Do you have benchmark results? How fast is it compared with futex_swap and the google switchto?

Hi Andrei,

I did not run benchmarks on the same machine/kernel, but umcg_swap
between "core" tasks (your use case for gVisor) should be somewhat
faster than futex_swap, as there is no reading from the userspace and
no futex hash lookup/dequeue ops; umcg_swap should be slower than
switchto_switch because umcg_swap does go through ttwu+schedule, which
switchto_switch bypasses.

I expect that if UMCG is merged in a form similar to what I posted, we
will explore how to make UMCG context switches faster in later
patches.

Thanks,
Peter

>
> Thanks,
> Andrei

  parent reply	other threads:[~2021-05-21 19:14 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-20 18:36 [RFC PATCH v0.1 0/9] UMCG early preview/RFC patchset Peter Oskolkov
2021-05-20 18:36 ` [RFC PATCH v0.1 1/9] sched/umcg: add UMCG syscall stubs and CONFIG_UMCG Peter Oskolkov
2021-05-22 18:40   ` kernel test robot
2021-05-22 21:49   ` kernel test robot
2021-05-20 18:36 ` [RFC PATCH v0.1 2/9] sched/umcg: add uapi/linux/umcg.h and sched/umcg.c Peter Oskolkov
2021-05-20 18:36 ` [RFC PATCH v0.1 3/9] sched: add WF_CURRENT_CPU and externise ttwu Peter Oskolkov
2021-05-20 18:36 ` [RFC PATCH v0.1 4/9] sched/umcg: implement core UMCG API Peter Oskolkov
2021-05-21 19:06   ` Andrei Vagin
2021-05-21 21:31     ` Jann Horn
2021-05-21 22:03       ` Peter Oskolkov
2021-05-21 19:32   ` Andy Lutomirski
2021-05-21 22:01     ` Peter Oskolkov
2021-05-21 21:33   ` Jann Horn
2021-06-09 13:01     ` Peter Zijlstra
2021-05-20 18:36 ` [RFC PATCH v0.1 5/9] lib/umcg: implement UMCG core API for userspace Peter Oskolkov
2021-05-20 18:36 ` [RFC PATCH v0.1 6/9] selftests/umcg: add UMCG core API selftest Peter Oskolkov
2021-05-20 18:36 ` [RFC PATCH v0.1 7/9] sched/umcg: add UMCG server/worker API (early RFC) Peter Oskolkov
2021-05-21 20:17   ` Andrei Vagin
2021-05-22 18:29   ` kernel test robot
2021-05-22 19:34   ` kernel test robot
2021-05-22 20:19   ` kernel test robot
2021-05-20 18:36 ` [RFC PATCH v0.1 8/9] lib/umcg: " Peter Oskolkov
2021-05-20 18:36 ` [RFC PATCH v0.1 9/9] selftests/umcg: add UMCG server/worker API selftest Peter Oskolkov
2021-05-20 21:17 ` [RFC PATCH v0.1 0/9] UMCG early preview/RFC patchset Jonathan Corbet
2021-05-20 21:38   ` Peter Oskolkov
2021-05-21  0:15     ` Randy Dunlap
2021-05-21  8:04       ` Peter Zijlstra
2021-05-21 15:08     ` Jonathan Corbet
2021-05-21 16:03       ` Peter Oskolkov
2021-05-21 19:17         ` Jonathan Corbet
2021-05-27  0:06           ` Peter Oskolkov
2021-05-27 15:41             ` Jonathan Corbet
     [not found] ` <CAEWA0a72SvpcuN4ov=98T3uWtExPCr7BQePOgjkqD1ofWKEASw@mail.gmail.com>
2021-05-21 19:13   ` Peter Oskolkov [this message]
2021-05-21 23:08     ` Jann Horn
2021-06-09 12:54 ` Peter Zijlstra
2021-06-09 20:18   ` Peter Oskolkov
2021-06-10 18:02     ` Peter Zijlstra
2021-06-10 20:06       ` Peter Oskolkov
2021-07-07 17:45       ` Thierry Delisle
2021-07-08 21:44         ` Peter Oskolkov

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