Re: [PATCH 2/3] [RFC] time: Fix leapsecond triggered hrtimer/futexload spike issue

[Prarit Bhargava]

On 07/04/2012 02:21 AM, John Stultz wrote:
> As widely reported on the internet, some Linux systems after
> the leapsecond was inserted are experiencing futex related load
> spikes (usually connected to MySQL, Firefox, Thunderbird, Java, etc).
> 
> An apparent for this issue workaround is running:
> $ date -s "`date`"
> 
> Credit: http://www.sheeri.com/content/mysql-and-leap-second-high-cpu-and-fix
> 
> I this issue is due to the leapsecond being added without
> calling clock_was_set() to notify the hrtimer subsystem of the
> change.
> 
> The workaround functions as it forces a clock_was_set()
> call from settimeofday().
> 
> This fix adds the required clock_was_set() calls to where
> we adjust for leapseconds.
> 
> NOTE: This fix *depends* on the previous fix, which allows
> clock_was_set to be called from atomic context. Do not try
> to apply just this patch.
> 
> CC: Prarit Bhargava <prarit@xxxxxxxxxx>
> CC: stable@xxxxxxxxxxxxxxx
> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> CC: linux@xxxxxxxxxxxxxx
> Reported-by: Jan Engelhardt <jengelh@xxxxxxx>
> Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>


Acked-by: Prarit Bhargava <prarit@xxxxxxxxxx>

P.
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