Re: [PATCH] Migration of standard timers

[Thomas Gleixner]

On Thu, 2006-09-14 at 08:29 -0500, Dimitri Sivanich wrote:
> This patch allows the user to migrate currently queued
> standard timers from one cpu to another, thereby reducing
> timer induced latency on the chosen cpu.  Timers that
> were placed with add_timer_on() are considered to have 
> 'cpu affinity' and are not moved.
> 
> The changes in drivers/base/cpu.c provide a clean and
> convenient interface for triggering the migration through
> sysfs, via writing the destination cpu number to a file
> associated with the source cpu.
> 
> Note that migrating timers will not, by itself, keep new
> timers off of the chosen cpu.  But with careful control of
> thread affinity, one can control the affinity of new timers
> and keep timer induced latencies off of the chosen cpu.
> 
> This particular patch does not affect the hrtimers.  That
> could be addressed later.

Are you trying to work around the latencies caused by long running timer
callbacks ? I'm not convinced that this is not curing the symptoms
instead of the root cause.

	tglx


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