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From: Ingo Molnar <mingo@elte.hu>
To: Andi Kleen <andi@firstfloor.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Andy Lutomirski <luto@MIT.EDU>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Borislav Petkov <bp@amd64.org>
Subject: Re: [PATCH v4 0/6] Micro-optimize vclock_gettime
Date: Tue, 17 May 2011 09:56:35 +0200	[thread overview]
Message-ID: <20110517075635.GA22093@elte.hu> (raw)
In-Reply-To: <20110516164939.GD25898@one.firstfloor.org>


* Andi Kleen <andi@firstfloor.org> wrote:

> > And unless you or someone else changes the primitive state of the
> > kernel, framepointers are going to stay simply because removing them
> > breaks profiling backtraces when the hit is inside vread().
> 
> This doesn't work anyways because the glibc stub code calling vgettimeofday 
> normally doesn't set up a frame pointer frame.

But we at least get a callchain back to that point.

Also, Thomas's point remains: you can whine about framepointers and you can try 
to slowly sabotage proper backtraces (nasty and sleazy tactic you are using 
there btw), or you can help out bring sane dwarf support to the kernel.

Thanks,

	Ingo

      parent reply	other threads:[~2011-05-17  7:56 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-16 16:00 [PATCH v4 0/6] Micro-optimize vclock_gettime Andy Lutomirski
2011-05-16 16:00 ` [PATCH v4 1/6] x86-64: Clean up vdso/kernel shared variables Andy Lutomirski
2011-05-16 17:23   ` Borislav Petkov
2011-05-16 17:34     ` Andrew Lutomirski
2011-05-16 16:00 ` [PATCH v4 2/6] x86-64: Remove unnecessary barrier in vread_tsc Andy Lutomirski
2011-05-16 16:01 ` [PATCH v4 3/6] x86-64: Don't generate cmov " Andy Lutomirski
2011-05-16 16:01 ` [PATCH v4 4/6] x86-64: vclock_gettime(CLOCK_MONOTONIC) can't ever see nsec < 0 Andy Lutomirski
2011-05-16 16:01 ` [PATCH v4 5/6] x86-64: Move vread_tsc into a new file with sensible options Andy Lutomirski
2011-05-16 16:01 ` [PATCH v4 6/6] x86-64: Turn off -pg and turn on -foptimize-sibling-calls for vDSO Andy Lutomirski
2011-05-16 16:09 ` [PATCH v4 0/6] Micro-optimize vclock_gettime Andi Kleen
2011-05-16 16:25   ` Thomas Gleixner
2011-05-16 16:49     ` Andi Kleen
2011-05-16 17:05       ` Andrew Lutomirski
2011-05-16 20:22         ` Andi Kleen
2011-05-16 21:28           ` Andrew Lutomirski
2011-05-16 21:53           ` Thomas Gleixner
2011-05-16 22:17             ` Andrew Lutomirski
2011-05-16 22:40               ` Thomas Gleixner
2011-05-17  8:00                 ` Ingo Molnar
2011-05-17 11:11                   ` Andrew Lutomirski
2011-05-17 11:36                     ` Ingo Molnar
2011-05-17 18:31                       ` Andy Lutomirski
2011-05-17 19:27                         ` Ingo Molnar
2011-05-17 21:31                         ` Andi Kleen
2011-05-17 22:59                           ` Thomas Gleixner
2011-05-18  3:18                             ` Andrew Lutomirski
2011-05-18  7:30                               ` Thomas Gleixner
2011-05-18  8:31                                 ` Ingo Molnar
2011-05-18 11:30                                   ` Andrew Lutomirski
2011-05-18 12:10                                     ` Ingo Molnar
2011-05-17  7:56       ` Ingo Molnar [this message]

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