From: Davidlohr Bueso <dave@stgolabs.net>
To: Denys Vlasenko <dvlasenk@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/signal: Deinline get_sigframe, save 240 bytes
Date: Mon, 28 Sep 2015 13:24:01 -0700 [thread overview]
Message-ID: <20150928202401.GB4035@linux-uzut.site> (raw)
In-Reply-To: <560943EF.4040407@redhat.com>
On Mon, 28 Sep 2015, Denys Vlasenko wrote:
>On 09/28/2015 02:33 PM, H. Peter Anvin wrote:
>> This one makes me slightly nervous, because it isn't clear
>> that these aren't potentially performance sensitive.
>
>CALL instruction is not a crime :)
>It costs about the same as one read-modify-write
>operation on a memory operand.
>
>This function is used in signal delivery code.
>If performance critical code uses massive numbers
>of signals, it already has a problem, Unix signals
>are too inefficient. That's why we have futexes etc...
True, but in general I don't think that justifies anything -- and not only
referring to this particular signal patch.
Nothing really against or in favor of these patches, but I don't think that
saving 240 bytes (or whatever) is worth such changes, in fact we have Josh's
tinyfication project for those systems that do in fact care.
Thanks,
Davidlohr
next prev parent reply other threads:[~2015-09-28 20:24 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-28 12:23 [PATCH] x86/apic: Deinline __x2apic_disable, save 467 bytes Denys Vlasenko
2015-09-28 12:23 ` [PATCH] x86: Deinline e820_type_to_string, save 126 bytes Denys Vlasenko
2015-09-30 19:57 ` [tip:x86/cleanups] x86/e820: " tip-bot for Denys Vlasenko
2015-09-28 12:23 ` [PATCH] x86: Deinline early_console_register, save 403 bytes Denys Vlasenko
2015-09-30 19:57 ` [tip:x86/cleanups] " tip-bot for Denys Vlasenko
2015-09-28 12:23 ` [PATCH] x86/signal: Deinline get_sigframe, save 240 bytes Denys Vlasenko
2015-09-28 12:33 ` H. Peter Anvin
2015-09-28 13:43 ` Denys Vlasenko
2015-09-28 20:24 ` Davidlohr Bueso [this message]
2015-09-29 18:54 ` Thomas Gleixner
2015-09-30 19:58 ` [tip:x86/cleanups] " tip-bot for Denys Vlasenko
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