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
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next prev parent reply other threads:[~2023-01-13 0:47 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAGudoHHx0Nqg6DE70zAVA75eV-HXfWyhVMWZ-aSeOofkA_=WdA@mail.gmail.com>
2023-01-13 0:13 ` lockref scalability on x86-64 vs cpu_relax Linus Torvalds
2023-01-13 0:30 ` Luck, Tony
2023-01-13 0:45 ` Linus Torvalds [this message]
2023-01-13 7:55 ` ia64 removal (was: Re: lockref scalability on x86-64 vs cpu_relax) Ard Biesheuvel
2023-01-13 16:17 ` Luck, Tony
2023-01-13 20:49 ` Jessica Clarke
2023-01-13 21:03 ` Luck, Tony
2023-01-13 21:04 ` Jessica Clarke
2023-01-13 21:05 ` John Paul Adrian Glaubitz
2023-01-13 23:25 ` Ard Biesheuvel
2023-01-14 11:24 ` Sedat Dilek
2023-01-14 11:28 ` Sedat Dilek
2023-01-15 0:27 ` Matthew Wilcox
2023-01-15 12:04 ` Sedat Dilek
2023-01-16 9:42 ` John Paul Adrian Glaubitz
2023-01-16 9:41 ` John Paul Adrian Glaubitz
2023-01-16 13:28 ` Matthew Wilcox
2023-01-16 9:40 ` 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 10:09 ` Ard Biesheuvel
2023-01-13 1:12 ` lockref scalability on x86-64 vs cpu_relax Mateusz Guzik
2023-01-13 4:08 ` Linus Torvalds
2023-01-13 9:46 ` Will Deacon
2023-01-13 3:20 ` Nicholas Piggin
2023-01-13 4:15 ` Linus Torvalds
2023-01-13 5:36 ` Nicholas Piggin
[not found] ` <1966767.1673878095@warthog.procyon.org.uk>
2023-01-16 15:09 ` Memory transaction instructions Matthew Wilcox
2023-01-16 16:59 ` Linus Torvalds
2023-01-18 9:05 ` David Howells
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 18:44 ` [PATCH] lockref: stop doing cpu_relax in the cmpxchg loop Mateusz Guzik
2023-01-13 21:47 ` Luck, Tony
2023-01-13 23:31 ` Linus Torvalds
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