From: Andi Kleen <andi@firstfloor.org>
To: Jiri Kosina <jkosina@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>,
Justin Piszcz <jpiszcz@lucidpixels.com>,
linux-kernel@vger.kernel.org
Subject: Re: What is the performance when using frame pointers in the kernel?
Date: Sun, 06 Dec 2009 23:31:03 +0100 [thread overview]
Message-ID: <874oo391lk.fsf@basil.nowhere.org> (raw)
In-Reply-To: <alpine.LRH.2.00.0912041422360.9567@twin.jikos.cz> (Jiri Kosina's message of "Fri, 4 Dec 2009 14:23:55 +0100 (CET)")
Jiri Kosina <jkosina@suse.cz> writes:
> On Thu, 3 Dec 2009, Peter Zijlstra wrote:
>
>> > What is the performance hit when the kernel is compiled with frame
>> > pointers?
>>
>> build both kernels and run your favourite workload to find out.
>
> But generally speaking, frame pointers impose quite some performance
> penalty indeed. lmbench syscall microbenchmark can give you some hint. I
> expect you'll see approx. 10% performance increase for various syscalls if
> you disable them, as that's what we have measured lately.
It'll depend on the CPU. On many common cores frame pointer cause
a a few cycles stall on each function entry, but not on all.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
prev parent reply other threads:[~2009-12-06 22:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-03 17:36 What is the performance when using frame pointers in the kernel? Justin Piszcz
2009-12-03 19:28 ` Peter Zijlstra
2009-12-04 13:23 ` Jiri Kosina
2009-12-04 15:25 ` Justin Piszcz
2009-12-05 7:02 ` Ingo Molnar
2009-12-06 22:31 ` Andi Kleen [this message]
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