Borislav Petkov 79a8b9aa38 x86/CPU/AMD: Bring back Compute Unit ID ... Commit: a33d331761 ("x86/CPU/AMD: Fix Bulldozer topology") restored the initial approach we had with the Fam15h topology of enumerating CU (Compute Unit) threads as cores. And this is still correct - they're beefier than HT threads but still have some shared functionality. Our current approach has a problem with the Mad Max Steam game, for example. Yves Dionne reported a certain "choppiness" while playing on v4.9.5. That problem stems most likely from the fact that the CU threads share resources within one CU and when we schedule to a thread of a different compute unit, this incurs latency due to migrating the working set to a different CU through the caches. When the thread siblings mask mirrors that aspect of the CUs and threads, the scheduler pays attention to it and tries to schedule within one CU first. Which takes care of the latency, of course. Reported-by: Yves Dionne <yves.dionne@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: <stable@vger.kernel.org> # 4.9 Cc: Brice Goglin <Brice.Goglin@inria.fr> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yazen Ghannam <yazen.ghannam@amd.com> Link: http://lkml.kernel.org/r/20170205105022.8705-1-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>		2017-02-05 12:18:45 +01:00
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asm	x86/CPU/AMD: Bring back Compute Unit ID	2017-02-05 12:18:45 +01:00
uapi/asm	Small release, the most interesting stuff is x86 nested virt improvements.	2016-12-13 15:47:02 -08:00