Re: [PATCH] x86/speculation: Revert turning on STIBP all the time

2018-11-21 Thread Greg KH
On Wed, Nov 21, 2018 at 09:51:19PM +0100, Jiri Kosina wrote: > On Wed, 21 Nov 2018, Tim Chen wrote: > > > Commit 53c613fe "x86/speculation: Enable cross-hyperthread spectre v2 STIBP > > mitigation" > > turns on STIBP all the time. > > > > This causes large performance regression in many workload

Re: [PATCH] x86/speculation: Revert turning on STIBP all the time

2018-11-21 Thread Linus Torvalds
On Wed, Nov 21, 2018 at 12:51 PM Jiri Kosina wrote: > > For -rc, I don't think we need to do this at this moment, given the > prctl+seccomp fixup is basically ready, do we? Agreed. Linus

Re: [PATCH] x86/speculation: Revert turning on STIBP all the time

2018-11-21 Thread Jiri Kosina
On Wed, 21 Nov 2018, Tim Chen wrote: > Commit 53c613fe "x86/speculation: Enable cross-hyperthread spectre v2 STIBP > mitigation" > turns on STIBP all the time. > > This causes large performance regression in many workloads. > > One case is perlbench in the SpecInt Rate 2006 test suite which sho

[PATCH] x86/speculation: Revert turning on STIBP all the time

2018-11-21 Thread Tim Chen
Commit 53c613fe "x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation" turns on STIBP all the time. This causes large performance regression in many workloads. One case is perlbench in the SpecInt Rate 2006 test suite which shows a 21% reduction in throughput. There're also othe