lkml.org 
[lkml]   [2010]   [Oct]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ACPI: Read TSC upon resume
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? I don't think it matches anything the kernel
community wants, do you?

And are you always going to be printing this out? Why do we want to
know this every time?


> Signed-off-by: Sameer Nanda <snanda@chromium.org>
> ---
> drivers/acpi/sleep.c | 4 ++++
> 1 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)
> acpi_status status = AE_OK;
> unsigned long flags = 0;
> u32 acpi_state = acpi_target_sleep_state;
> + u64 tsc;
>
> ACPI_FLUSH_CPU_CACHE();
>
> @@ -235,6 +236,9 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
>
> case ACPI_STATE_S3:
> do_suspend_lowlevel();
> + rdtscll(tsc);
> + printk(KERN_INFO "TSC at resume: %llu\n",
> + (unsigned long long)tsc);

How long does this take, will it slow down resume?

thanks,

greg k-h


\
 
 \ /
  Last update: 2010-10-07 04:27    [from the cache]
©2003-2011 Jasper Spaans