Messages in this thread | | | Subject | Re: [Cbe-oss-dev] powerpc/cell/oprofile: fix mutex locking for spu-oprofile | From | Michael Ellerman <> | Date | Thu, 21 Aug 2008 20:20:10 +1000 |
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On Thu, 2008-08-21 at 10:14 +0200, Arnd Bergmann wrote: > On Thursday 21 August 2008, Paul Mackerras wrote: > > Arnd Bergmann writes: > > > > > Paul, any chance we can still get this into 2.6.27? > > > > Possibly. We'll need a really good explanation for Linus as to why > > this is needed (what regression or serious bug this fixes) and why it > > is late. Can you send me something explaining that? > > The patch does not fix a regression, the spu-oprofile code basically never > worked. With the current code in Linux, samples in the profile buffer > can get corrupted because reader and writer to that buffer use different > locks for accessing it.
Actually for me it worked[1] a reasonable amount of the time, enough to be useful. So the spu-oprofile code has always been broken in this way, but it's not always fatal. So the patch doesn't fix a regression, but it fixes a serious user-visible bug, which makes it legit rc4 material IMHO.
[1] that was late last year, so possibly a kernel or two ago.
cheers
-- Michael Ellerman OzLabs, IBM Australia Development Lab
wwweb: http://michael.ellerman.id.au phone: +61 2 6212 1183 (tie line 70 21183)
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