Messages in this thread Patch in this message | | | Subject | Re: [PATCH REGRESSION FIX] x86 idle: restore mwait_idle() | From | Mike Galbraith <> | Date | Sat, 18 Jan 2014 17:14:44 +0100 |
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On Sat, 2014-01-18 at 10:33 +0100, Mike Galbraith wrote: > On Fri, 2014-01-17 at 05:20 +0100, Mike Galbraith wrote: > > > taskset 0xc pipe-test 1 > > > > 3.8.13 3.397977 usecs/loop -- avg 3.400336 588.2 KHz > > master+ 4.798547 usecs/loop -- avg 4.791692 417.4 KHz > > Bah, those are apple/grape, these are apple/apple.
Or, to make it more correct for 3.10..13, add the clflush barriers as well for afflicted CPUs.
idle: kill unnecessary mwait_idle() resched IPIs
Set/clear polling instead.
Q6600, pipe-test scheduling cross core: 3.8.13 487.2 KHz 1.000 3.13.0-master 415.5 KHz .852 3.13.0-master+ 415.2 KHz .852 + restore mwait_idle 3.13.0-master++ 488.5 KHz 1.002 + restore mwait_idle + IPI fix
Signed-off-by: Mike Galbraith <bitbucket@online.de> Cc: <stable@vger.kernel.org> # 3.10+ --- arch/x86/kernel/process.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -427,18 +427,21 @@ static int prefer_mwait_c1_over_halt(con static void mwait_idle(void) { - if (!need_resched()) { - if (this_cpu_has(X86_FEATURE_CLFLUSH_MONITOR)) + if (!current_set_polling_and_test()) { + if (this_cpu_has(X86_FEATURE_CLFLUSH_MONITOR)) { + mb(); clflush((void *)¤t_thread_info()->flags); + mb(); + } __monitor((void *)¤t_thread_info()->flags, 0, 0); - smp_mb(); if (!need_resched()) __sti_mwait(0, 0); else local_irq_enable(); } else local_irq_enable(); + __current_clr_polling(); } void select_idle_routine(const struct cpuinfo_x86 *c)
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