Re: [PATCH v4.4] x86/kconfig: Fall back to ticket spinlocks

2018-11-10 Thread Greg Kroah-Hartman
On Wed, Oct 31, 2018 at 09:14:58AM +0100, Daniel Wagner wrote: > From: Daniel Wagner > > Sebastian writes: > > """ > We reproducibly observe cache line starvation on a Core2Duo E6850 (2 > cores), a i5-6400 SKL (4 cores) and on a NXP LS2044A ARM Cortex-A72 (4 > cores). > > The problem can be tri

Re: [PATCH v4.4] x86/kconfig: Fall back to ticket spinlocks

2018-11-01 Thread Peter Zijlstra
On Wed, Oct 31, 2018 at 09:14:58AM +0100, Daniel Wagner wrote: > From: Daniel Wagner > > Sebastian writes: > > """ > We reproducibly observe cache line starvation on a Core2Duo E6850 (2 > cores), a i5-6400 SKL (4 cores) and on a NXP LS2044A ARM Cortex-A72 (4 > cores). > > The problem can be tri

Re: [PATCH v4.4] x86/kconfig: Fall back to ticket spinlocks

2018-11-01 Thread Thomas Gleixner
On Wed, 31 Oct 2018, Daniel Wagner wrote: > Backporting all qspinlock related patches is very likely to introduce > regressions on v4.4. Therefore, the recommended solution by Peter and > Thomas is to drop back to ticket spinlocks for v4.4. > > Link :https://lkml.kernel.org/r/20180921120226.6xjgr4

[PATCH v4.4] x86/kconfig: Fall back to ticket spinlocks

2018-10-31 Thread Daniel Wagner
From: Daniel Wagner Sebastian writes: """ We reproducibly observe cache line starvation on a Core2Duo E6850 (2 cores), a i5-6400 SKL (4 cores) and on a NXP LS2044A ARM Cortex-A72 (4 cores). The problem can be triggered with a v4.9-RT kernel by starting cyclictest -S -p98 -m -i2000 -b 200