From: Denys Vlasenko <dvlasenk@redhat.com>
To: "H. Peter Anvin" <hpa@zytor.com>, linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Andy Lutomirski <luto@amacapital.net>,
Frederic Weisbecker <fweisbec@gmail.com>, X86 ML <x86@kernel.org>,
Alexei Starovoitov <ast@plumgrid.com>,
Will Drewry <wad@chromium.org>, Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v3 0/8] x86: entry_64.S: always allocate complete "struct pt_regs"
Date: Wed, 06 Aug 2014 17:07:52 +0200 [thread overview]
Message-ID: <53E244C8.1030309@redhat.com> (raw)
In-Reply-To: <53E13AD9.5080908@zytor.com>
On 08/05/2014 10:13 PM, H. Peter Anvin wrote:
> On 08/05/2014 07:52 AM, Denys Vlasenko wrote:
>> Version 3 of the patchset.
>>
>> Please consider applying at least two first patches, they are definitely safe,
>> and the second one fixes a latent bug.
>>
>
> Please do provide latency measurements. I highly suspect that they will
> turn out that that this has no significant impact on latency, but we
> need to know for sure.
I ran tests in totally quiescent state (booted in /bin/sh)
on dual Core i7:
vendor_id : GenuineIntel
cpu family : 6
model : 42
model name : Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz
stepping : 7
microcode : 0x29
"timing_test32 20 getpid" command, best time:
old kernel 266.88 ns per getpid syscall
new kernel 265.95 ns per getpid syscall
"timing_test64 20 getpid" command, best time:
old kernel 54.12 ns per getpid syscall
new kernel 54.30 ns per getpid syscall
In both cases, run-to-run test variability is about 2 ns.
prev parent reply other threads:[~2014-08-06 15:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-05 14:52 [PATCH v3 0/8] x86: entry_64.S: always allocate complete "struct pt_regs" Denys Vlasenko
2014-08-05 14:52 ` [PATCH 1/8] x86: entry_64.S: delete unused code Denys Vlasenko
2014-08-05 14:52 ` [PATCH 2/8] x86: ia32entry.S: fix wrong symbolic constant usage: R11->ARGOFFSET Denys Vlasenko
2014-08-05 14:52 ` [PATCH 3/8] x86: open-code register save/restore in trace_hardirqs thunks Denys Vlasenko
2014-08-05 14:52 ` [PATCH 4/8] x86: entry_64.S: fold SAVE_ARGS_IRQ macro into its sole user Denys Vlasenko
2014-08-05 14:52 ` [PATCH 5/8] x86: entry_64.S: always allocate complete "struct pt_regs" Denys Vlasenko
2014-08-05 14:52 ` [PATCH 6/8] x86: mass removal of ARGOFFSET Denys Vlasenko
2014-08-05 14:52 ` [PATCH 7/8] x86: rename some macros and labels, no code changes Denys Vlasenko
2014-08-05 14:52 ` [PATCH 8/8] x86: add comments about various syscall instructions, " Denys Vlasenko
2014-08-05 19:58 ` Oleg Nesterov
2014-08-08 16:18 ` Denys Vlasenko
2014-08-05 20:13 ` [PATCH v3 0/8] x86: entry_64.S: always allocate complete "struct pt_regs" H. Peter Anvin
2014-08-06 15:07 ` Denys Vlasenko [this message]
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