(resending as plain text, sorry if you got dupe messages) On Wed, Oct 6, 2010 at 7:19 PM, Greg KH <gregkh@xxxxxxx> wrote: > On Wed, Oct 06, 2010 at 04:15:19PM -0700, Sameer Nanda wrote: >> Read the TSC upon resuming and print it out. This is useful >> in helping figure out amount of time spent in the BIOS when >> resuming from suspend. >> >> Change-Id: I1d6a32bd62421becddecd152d561763e5f3e1101 > > What is this tag for? ÂI don't think it matches anything the kernel > community wants, do you? Yeah, its not needed. Let me resubmit the patch without this tag. > > And are you always going to be printing this out? ÂWhy do we want to > know this every time? Yes, every time. This helps track variance in BIOS resume times within a single boot. > >> Signed-off-by: Sameer Nanda <snanda@xxxxxxxxxxxx> >> --- >> Âdrivers/acpi/sleep.c | Â Â4 ++++ >> Â1 files changed, 4 insertions(+), 0 deletions(-) >> >> diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c >> index c0fed2e..f0588fa 100644 >> --- a/drivers/acpi/sleep.c >> +++ b/drivers/acpi/sleep.c >> @@ -214,6 +214,7 @@ static int acpi_suspend_enter(suspend_state_t pm_state) >> Â Â Â acpi_status status = AE_OK; >> Â Â Â unsigned long flags = 0; >> Â Â Â u32 acpi_state = acpi_target_sleep_state; >> + Â Â u64 tsc; >> >> Â Â Â ACPI_FLUSH_CPU_CACHE(); >> >> @@ -235,6 +236,9 @@ static int acpi_suspend_enter(suspend_state_t pm_state) >> >> Â Â Â case ACPI_STATE_S3: >> Â Â Â Â Â Â Â do_suspend_lowlevel(); >> + Â Â Â Â Â Â rdtscll(tsc); >> + Â Â Â Â Â Â printk(KERN_INFO "TSC at resume: %llu\n", >> + Â Â Â Â Â Â Â Â Â Â Â Â Â Â (unsigned long long)tsc); > > How long does this take, will it slow down resume? The impact is ~10us (as measured on an Intel Atom N455 @ 1.66Ghz). Given that resume time is currently of the order of 1sec, its in the noise range. Thanks for the feedback! > > thanks, > > greg k-h > -- Sameer -- 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
