From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Jan Beulich <JBeulich@novell.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/6] x86,64: Simplify save_regs()
Date: Wed, 06 Jul 2011 11:20:49 -0700 [thread overview]
Message-ID: <4E14A781.8090004@zytor.com> (raw)
In-Reply-To: <m2sjqj71ot.fsf@firstfloor.org>
On 07/06/2011 10:34 AM, Andi Kleen wrote:
> Frederic Weisbecker <fweisbec@gmail.com> writes:
>>
>> I really did not think about code duplication, considering
>> it's better to optimize the irq entry path.
>>
>> What do you guys think? We can still revert the whole patchset.
>
> FWIW I think it should be a macro, like it was in the original code.
>
> Optimizing entry*.S for code size doesn't make a lot of sense.
>
Code size, no.
*Path* size and cache/prefetch friendliness is another matter.
The subroutine is bad on that account, too, so yes, this really seems
like a losing proposition.
I'm not too fond of the gajillion obtuse macros we have, but subroutines
doesn't make it really any better.
-hpa
next prev parent reply other threads:[~2011-07-06 18:21 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-02 16:29 [RFC GIT PULL] x86 entry / perf stacktrace changes Frederic Weisbecker
2011-07-02 16:29 ` [PATCH 1/6] x86: Save stack pointer in perf live regs savings Frederic Weisbecker
2011-07-02 16:29 ` [PATCH 2/6] x86: Fetch stack from regs when possible in dump_trace() Frederic Weisbecker
2011-07-02 16:29 ` [PATCH 3/6] x86,64: Simplify save_regs() Frederic Weisbecker
2011-07-04 7:20 ` Jan Beulich
2011-07-04 12:57 ` Frederic Weisbecker
2011-07-06 17:34 ` Andi Kleen
2011-07-06 18:20 ` H. Peter Anvin [this message]
2011-07-06 20:42 ` Frederic Weisbecker
2011-07-04 12:59 ` Frederic Weisbecker
2011-07-02 16:29 ` [PATCH 4/6] x86,64: Separate arg1 from rbp handling in SAVE_REGS_IRQ Frederic Weisbecker
2011-07-04 7:34 ` Jan Beulich
2011-07-02 16:29 ` [PATCH 5/6] x86: Remove useless unwinder backlink from irq regs saving Frederic Weisbecker
2011-07-04 7:29 ` Jan Beulich
2011-07-04 9:17 ` Ingo Molnar
2011-07-04 13:10 ` Frederic Weisbecker
2011-07-04 13:22 ` Frederic Weisbecker
2011-07-05 22:21 ` Valdis.Kletnieks
2011-07-02 16:29 ` [PATCH 6/6] x86: Don't use frame pointer to save old stack on irq entry Frederic Weisbecker
2011-07-04 9:13 ` [RFC GIT PULL] x86 entry / perf stacktrace changes Ingo Molnar
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