From: Linus Torvalds <torvalds@linux-foundation.org>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>,
linux-arch <linux-arch@vger.kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
Jan Glauber <jan.glauber@gmail.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: lockref scalability on x86-64 vs cpu_relax
Date: Thu, 12 Jan 2023 18:45:55 -0600 [thread overview]
Message-ID: <CAHk-=wg6opc5nb1qMuCO-R36Pfz_JJbx1DsU1P0cvLAeM2+eLQ@mail.gmail.com> (raw)
In-Reply-To: <SJ1PR11MB6083368BCA43E5B0D2822FD3FCC29@SJ1PR11MB6083.namprd11.prod.outlook.com>
On Thu, Jan 12, 2023 at 6:31 PM Luck, Tony <tony.luck@intel.com> wrote:
>
> There's not much "simultaneous" in the SMT on ia64.
Oh, I forgot about the whole SoEMT fiasco.
Yeah, that might make ia64 act a bit differently here.
But I don't think anybody cares any more, so I don't think that merits
making this a per-architecture choice.
The s390 people hated cpu_relax() here, but for them it was really
because it was bad *everywhere*, and they just made it a no-op (see
commit 22b6430d3665 "locking/core, s390: Make cpu_relax() a barrier
again"). There had been a (failed) attempt at "cpu_relax_lowlatency()"
for the s390 issues.
Linus
WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: linux-arch <linux-arch@vger.kernel.org>,
Mateusz Guzik <mjguzik@gmail.com>,
Catalin Marinas <catalin.marinas@arm.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Jan Glauber <jan.glauber@gmail.com>,
Will Deacon <will@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: lockref scalability on x86-64 vs cpu_relax
Date: Thu, 12 Jan 2023 18:45:55 -0600 [thread overview]
Message-ID: <CAHk-=wg6opc5nb1qMuCO-R36Pfz_JJbx1DsU1P0cvLAeM2+eLQ@mail.gmail.com> (raw)
In-Reply-To: <SJ1PR11MB6083368BCA43E5B0D2822FD3FCC29@SJ1PR11MB6083.namprd11.prod.outlook.com>
On Thu, Jan 12, 2023 at 6:31 PM Luck, Tony <tony.luck@intel.com> wrote:
>
> There's not much "simultaneous" in the SMT on ia64.
Oh, I forgot about the whole SoEMT fiasco.
Yeah, that might make ia64 act a bit differently here.
But I don't think anybody cares any more, so I don't think that merits
making this a per-architecture choice.
The s390 people hated cpu_relax() here, but for them it was really
because it was bad *everywhere*, and they just made it a no-op (see
commit 22b6430d3665 "locking/core, s390: Make cpu_relax() a barrier
again"). There had been a (failed) attempt at "cpu_relax_lowlatency()"
for the s390 issues.
Linus
WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>,
linux-arch <linux-arch@vger.kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
Jan Glauber <jan.glauber@gmail.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: lockref scalability on x86-64 vs cpu_relax
Date: Thu, 12 Jan 2023 18:45:55 -0600 [thread overview]
Message-ID: <CAHk-=wg6opc5nb1qMuCO-R36Pfz_JJbx1DsU1P0cvLAeM2+eLQ@mail.gmail.com> (raw)
In-Reply-To: <SJ1PR11MB6083368BCA43E5B0D2822FD3FCC29@SJ1PR11MB6083.namprd11.prod.outlook.com>
On Thu, Jan 12, 2023 at 6:31 PM Luck, Tony <tony.luck@intel.com> wrote:
>
> There's not much "simultaneous" in the SMT on ia64.
Oh, I forgot about the whole SoEMT fiasco.
Yeah, that might make ia64 act a bit differently here.
But I don't think anybody cares any more, so I don't think that merits
making this a per-architecture choice.
The s390 people hated cpu_relax() here, but for them it was really
because it was bad *everywhere*, and they just made it a no-op (see
commit 22b6430d3665 "locking/core, s390: Make cpu_relax() a barrier
again"). There had been a (failed) attempt at "cpu_relax_lowlatency()"
for the s390 issues.
Linus
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2023-01-13 0:46 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-12 23:36 lockref scalability on x86-64 vs cpu_relax Mateusz Guzik
2023-01-13 0:13 ` Linus Torvalds
2023-01-13 0:13 ` Linus Torvalds
2023-01-13 0:13 ` Linus Torvalds
2023-01-13 0:30 ` Luck, Tony
2023-01-13 0:30 ` Luck, Tony
2023-01-13 0:30 ` Luck, Tony
2023-01-13 0:45 ` Linus Torvalds [this message]
2023-01-13 0:45 ` Linus Torvalds
2023-01-13 0:45 ` Linus Torvalds
2023-01-13 7:55 ` ia64 removal (was: Re: lockref scalability on x86-64 vs cpu_relax) Ard Biesheuvel
2023-01-13 7:55 ` Ard Biesheuvel
2023-01-13 7:55 ` Ard Biesheuvel
2023-01-13 16:17 ` Luck, Tony
2023-01-13 16:17 ` Luck, Tony
2023-01-13 16:17 ` Luck, Tony
2023-01-13 20:49 ` Jessica Clarke
2023-01-13 20:49 ` Jessica Clarke
2023-01-13 20:49 ` Jessica Clarke
2023-01-13 21:03 ` Luck, Tony
2023-01-13 21:03 ` Luck, Tony
2023-01-13 21:03 ` Luck, Tony
2023-01-13 21:04 ` Jessica Clarke
2023-01-13 21:04 ` Jessica Clarke
2023-01-13 21:04 ` Jessica Clarke
2023-01-13 21:05 ` John Paul Adrian Glaubitz
2023-01-13 21:05 ` John Paul Adrian Glaubitz
2023-01-13 21:05 ` John Paul Adrian Glaubitz
2023-01-13 23:25 ` Ard Biesheuvel
2023-01-13 23:25 ` Ard Biesheuvel
2023-01-13 23:25 ` Ard Biesheuvel
2023-01-14 11:24 ` Sedat Dilek
2023-01-14 11:24 ` Sedat Dilek
2023-01-14 11:24 ` Sedat Dilek
2023-01-14 11:28 ` Sedat Dilek
2023-01-14 11:28 ` Sedat Dilek
2023-01-14 11:28 ` Sedat Dilek
2023-01-15 0:27 ` Matthew Wilcox
2023-01-15 0:27 ` Matthew Wilcox
2023-01-15 0:27 ` Matthew Wilcox
2023-01-15 12:04 ` Sedat Dilek
2023-01-15 12:04 ` Sedat Dilek
2023-01-15 12:04 ` Sedat Dilek
2023-01-16 9:42 ` John Paul Adrian Glaubitz
2023-01-16 9:42 ` John Paul Adrian Glaubitz
2023-01-16 9:42 ` John Paul Adrian Glaubitz
2023-01-16 9:41 ` John Paul Adrian Glaubitz
2023-01-16 9:41 ` John Paul Adrian Glaubitz
2023-01-16 9:41 ` John Paul Adrian Glaubitz
2023-01-16 13:28 ` Matthew Wilcox
2023-01-16 13:28 ` Matthew Wilcox
2023-01-16 13:28 ` Matthew Wilcox
2023-01-16 9:40 ` John Paul Adrian Glaubitz
2023-01-16 9:40 ` John Paul Adrian Glaubitz
2023-01-16 9:40 ` John Paul Adrian Glaubitz
2023-01-16 9:37 ` John Paul Adrian Glaubitz
2023-01-16 9:37 ` John Paul Adrian Glaubitz
2023-01-16 9:37 ` John Paul Adrian Glaubitz
2023-01-16 9:32 ` John Paul Adrian Glaubitz
2023-01-16 9:32 ` John Paul Adrian Glaubitz
2023-01-16 9:32 ` John Paul Adrian Glaubitz
2023-01-16 10:09 ` Ard Biesheuvel
2023-01-16 10:09 ` Ard Biesheuvel
2023-01-16 10:09 ` Ard Biesheuvel
2023-01-13 1:12 ` lockref scalability on x86-64 vs cpu_relax Mateusz Guzik
2023-01-13 1:12 ` Mateusz Guzik
2023-01-13 1:12 ` Mateusz Guzik
2023-01-13 4:08 ` Linus Torvalds
2023-01-13 4:08 ` Linus Torvalds
2023-01-13 4:08 ` Linus Torvalds
2023-01-13 9:46 ` Will Deacon
2023-01-13 9:46 ` Will Deacon
2023-01-13 9:46 ` Will Deacon
2023-01-13 3:20 ` Nicholas Piggin
2023-01-13 3:20 ` Nicholas Piggin
2023-01-13 3:20 ` Nicholas Piggin
2023-01-13 4:15 ` Linus Torvalds
2023-01-13 4:15 ` Linus Torvalds
2023-01-13 4:15 ` Linus Torvalds
2023-01-13 5:36 ` Nicholas Piggin
2023-01-13 5:36 ` Nicholas Piggin
2023-01-13 5:36 ` Nicholas Piggin
2023-01-16 14:08 ` Memory transaction instructions David Howells
2023-01-16 14:08 ` David Howells
2023-01-16 15:09 ` Matthew Wilcox
2023-01-16 15:09 ` Matthew Wilcox
2023-01-16 15:09 ` Matthew Wilcox
2023-01-16 16:59 ` Linus Torvalds
2023-01-16 16:59 ` Linus Torvalds
2023-01-16 16:59 ` Linus Torvalds
2023-01-18 9:05 ` David Howells
2023-01-18 9:05 ` David Howells
2023-01-18 9:05 ` David Howells
2023-01-19 1:41 ` Nicholas Piggin
2023-01-19 1:41 ` Nicholas Piggin
2023-01-19 1:41 ` Nicholas Piggin
2023-01-13 10:23 ` lockref scalability on x86-64 vs cpu_relax Peter Zijlstra
2023-01-13 10:23 ` Peter Zijlstra
2023-01-13 10:23 ` Peter Zijlstra
2023-01-13 18:44 ` [PATCH] lockref: stop doing cpu_relax in the cmpxchg loop Mateusz Guzik
2023-01-13 18:44 ` Mateusz Guzik
2023-01-13 18:44 ` Mateusz Guzik
2023-01-13 21:47 ` Luck, Tony
2023-01-13 21:47 ` Luck, Tony
2023-01-13 21:47 ` Luck, Tony
2023-01-13 23:31 ` Linus Torvalds
2023-01-13 23:31 ` Linus Torvalds
2023-01-13 23:31 ` Linus Torvalds
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='CAHk-=wg6opc5nb1qMuCO-R36Pfz_JJbx1DsU1P0cvLAeM2+eLQ@mail.gmail.com' \
--to=torvalds@linux-foundation.org \
--cc=catalin.marinas@arm.com \
--cc=jan.glauber@gmail.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mjguzik@gmail.com \
--cc=mpe@ellerman.id.au \
--cc=tony.luck@intel.com \
--cc=viro@zeniv.linux.org.uk \
--cc=will@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.