oprofile: remove double ring buffering
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From: Steven Rostedt on 20 Mar 2010 00:50 On Sat, 2010-03-20 at 01:03 +0100, Andi Kleen wrote: > [This is currently being tested if it fixes the excessive samples > dropping I have been complaining about for some time. Still wanted > to post the patch for review.] > > commit 49e66e8ab54f1114237e6dc24dc32ac912870c41 > Author: Andi Kleen <ak(a)linux.intel.com> > Date: Fri Mar 19 21:03:48 2010 +0100 > > oprofile: remove double ring buffering > > oprofile used a double buffer scheme for its cpu event buffer > to avoid races on reading with the old lock less ring buffer. The old ring buffer was not lockless, hence the need for two ring buffers because of NMIs. The new ring buffer is lockless. > > But that is obsolete now with the new ring buffer, so simply > use a single buffer. This greatly simplifies the code and avoids > some situations where samples could be dropped. > > Based on suggestions from Steven Rostedt Acked-by: Steven Rostedt <rostedt(a)goodmis.org> -- Steve > > Signed-off-by: Andi Kleen <ak(a)linux.intel.com> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andi Kleen on 20 Mar 2010 01:00 On Sat, Mar 20, 2010 at 12:45:20AM -0400, Steven Rostedt wrote: > On Sat, 2010-03-20 at 01:03 +0100, Andi Kleen wrote: > > [This is currently being tested if it fixes the excessive samples > > dropping I have been complaining about for some time. Still wanted > > to post the patch for review.] > > > > commit 49e66e8ab54f1114237e6dc24dc32ac912870c41 > > Author: Andi Kleen <ak(a)linux.intel.com> > > Date: Fri Mar 19 21:03:48 2010 +0100 > > > > oprofile: remove double ring buffering > > > > oprofile used a double buffer scheme for its cpu event buffer > > to avoid races on reading with the old lock less ring buffer. > > The old ring buffer was not lockless, hence the need for two ring > buffers because of NMIs. The new ring buffer is lockless. Thanks. Description fixed. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Robert Richter on 1 Apr 2010 15:10 On 01.04.10 03:17:25, Andi Kleen wrote: > Got confirmation now this patch fixes most of the dropped oprofile > samples problem on a particular intensive test on a large system. > So now submitting the previous RFC formally. > .34 / Stable candidate. Thanks Andi, will take a look at this next week. -Robert -- Advanced Micro Devices, Inc. Operating System Research Center email: robert.richter(a)amd.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Steven Rostedt on 1 Apr 2010 15:20 On Thu, 2010-04-01 at 21:02 +0200, Robert Richter wrote: > On 01.04.10 03:17:25, Andi Kleen wrote: > > Got confirmation now this patch fixes most of the dropped oprofile > > samples problem on a particular intensive test on a large system. > > So now submitting the previous RFC formally. > > .34 / Stable candidate. > > Thanks Andi, will take a look at this next week. Note, I just sent out a patch set yesterday which will conflict with this change. I Cc'd both you and Andi on that patch. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andi Kleen on 4 Apr 2010 06:10
On Thu, Apr 01, 2010 at 03:11:24PM -0400, Steven Rostedt wrote: > On Thu, 2010-04-01 at 21:02 +0200, Robert Richter wrote: > > On 01.04.10 03:17:25, Andi Kleen wrote: > > > Got confirmation now this patch fixes most of the dropped oprofile > > > samples problem on a particular intensive test on a large system. > > > So now submitting the previous RFC formally. > > > .34 / Stable candidate. > > > > Thanks Andi, will take a look at this next week. > > Note, I just sent out a patch set yesterday which will conflict with > this change. > > I Cc'd both you and Andi on that patch. Steve, is your ring buffer patch intended for stable? I plan to submit the oprofile patch for stable and if your is not it would be more convenient if your patch was based on mine instead of the other way round. If yours is for stable I can rebase on top of yours. Thanks, -Andi -- ak(a)linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |