Messages in this thread | | | Date | Wed, 30 Aug 2017 21:30:07 +0900 | From | Sergey Senozhatsky <> | Subject | Re: possible circular locking dependency detected [was: linux-next: Tree for Aug 22] |
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Hello Peter,
On (08/30/17 10:47), Peter Zijlstra wrote: [..] > On Wed, Aug 30, 2017 at 10:42:07AM +0200, Peter Zijlstra wrote: > > > > So the overhead looks to be spread out over all sorts, which makes it > > harder to find and fix. > > > > stack unwinding is done lots and is fairly expensive, I've not yet > > checked if crossrelease does too much of that. > > Aah, we do an unconditional stack unwind for every __lock_acquire() now. > It keeps a trace in the xhlocks[]. > > Does the below cure most of that overhead?
thanks.
mostly yes. the kernel is not so dramatically slower now. it's still seems to be a bit slower, which is expected I suppose, but over all it's much better
real 1m35.209s user 4m12.467s sys 0m49.457s
// approx 10 seconds slower.
-ss
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