applied. thanks, -len On Friday 29 February 2008, Venki Pallipadi wrote: > On Fri, Feb 22, 2008 at 09:03:55AM -0800, Pallipadi, Venkatesh wrote: > > > > > > >-----Original Message----- > > >From: Jan Willies [mailto:jan@xxxxxxxxxxxx] > > >Sent: Friday, February 22, 2008 7:56 AM > > >To: Rafael J. Wysocki > > >Cc: linux-acpi@xxxxxxxxxxxxxxx; Ingo Molnar; LKML; Thomas > > >Gleixner; Pallipadi, Venkatesh > > >Subject: Re: 100% C0 with 2.6.25-rc > > > > > >Rafael J. Wysocki wrote: > > >> On Thursday, 21 of February 2008, Jan Willies wrote: > > >>> Since 2.6.25-rc1 I have a lot of wakeups/s (≈134191,4) and > > >spend 100% in C0. > > >>> It worked fine with 2.6.24 and commandline nolapic. Without > > >nolapic I had 80k > > >>> wakeups/s after some time, but not right from the start like now. > > >> > > >> We have a regression from 2.6.24, apparently interrupts-related. > > > > > >After a lot of bisecting I've found the bad commit: > > > > > >9b12e18cdc1553de62d931e73443c806347cd974 is first bad commit > > >commit 9b12e18cdc1553de62d931e73443c806347cd974 > > >Author: venkatesh.pallipadi@xxxxxxxxx <venkatesh.pallipadi@xxxxxxxxx> > > >Date: Thu Jan 31 17:35:05 2008 -0800 > > > > > > ACPI: cpuidle: Support C1 idle time accounting > > > > > > Show C1 idle time in /sysfs cpuidle interface. C1 idle time may not > > > be entirely accurate in all cases. It includes the time spent > > > in the interrupt handler after wakeup with "hlt" based C1. > > >But, it will > > > be accurate with "mwait" based C1. > > > > > > > > >Reverting the commit brings my laptop back to C2. > > > > > > > Thanks for the bisect info. I will look at the bad side effects that patch > > may be having and I should have a patch for you to test later today.... > > > > Jan replied later on this issue that he is not able to reproduce this problem > any more. Looking at the above, I could see a potential problem where > menu governor may get confused by the C-state residency time from poll > idle or C1 idle, where this timing info is not accurate. This inaccuracy is > due to interrupts being handled before we account for C-state exit. > > Patch below fixes this and is needed regardless of the issue pointed out by > Jan Willies here. But, I am suspecting that the patch will also fix the > problem reported by Jan. > > Do not mark TIME_VALID for CO poll state. > Mark C1 time as valid only with mwait (CSTATE_FFH) entry method. > > This makes governors use the timing information only when it is correct and > eliminates any wrong policy decisions that may result from invalid timing > information. > > Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx> > > Index: linux-2.6.git/drivers/acpi/processor_idle.c > =================================================================== > --- linux-2.6.git.orig/drivers/acpi/processor_idle.c 2008-02-15 02:18:14.000000000 -0800 > +++ linux-2.6.git/drivers/acpi/processor_idle.c 2008-02-26 07:02:30.000000000 -0800 > @@ -1686,7 +1686,9 @@ > switch (cx->type) { > case ACPI_STATE_C1: > state->flags |= CPUIDLE_FLAG_SHALLOW; > - state->flags |= CPUIDLE_FLAG_TIME_VALID; > + if (cx->entry_method == ACPI_CSTATE_FFH) > + state->flags |= CPUIDLE_FLAG_TIME_VALID; > + > state->enter = acpi_idle_enter_c1; > dev->safe_state = state; > break; > Index: linux-2.6.git/drivers/cpuidle/cpuidle.c > =================================================================== > --- linux-2.6.git.orig/drivers/cpuidle/cpuidle.c 2008-02-15 02:18:14.000000000 -0800 > +++ linux-2.6.git/drivers/cpuidle/cpuidle.c 2008-02-22 03:59:01.000000000 -0800 > @@ -224,7 +224,7 @@ > state->exit_latency = 0; > state->target_residency = 0; > state->power_usage = -1; > - state->flags = CPUIDLE_FLAG_POLL | CPUIDLE_FLAG_TIME_VALID; > + state->flags = CPUIDLE_FLAG_POLL; > state->enter = poll_idle; > } > #else > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
