Re: [PATCH 0/4] Rework alarm timer infrastrucure -take2

Dor Laor
2007-08-19T07:36:01Z

>I think this is a really nice and important patch set. Just a couple
>things:
>
>On Sun, 2007-08-19 at 00:02 +0200, Luca Tettamanti wrote:
>
>> > In this case the dyn-tick minimum res will be 1msec. I believe it
>should
>> > work ok since this is the case without any dyn-tick.
>>
>> Actually minimum resolution depends on host HZ setting, but - yes -
>> essentially you have the same behaviour of the "unix" timer, plus the
>> overhead of reprogramming the timer.
>
>Is this significant? At a high guest HZ, this is could be quite a lot
>of additional syscalls right?
>

I believe it's no significant since without dyn-tick the guest will get
the
same amount of signals so the overhead is doubling the syscalls (not a
magnitude bigger).

On the other size guests with low HZ and linux guests with dyn-tick will
enojy
from lesser syscalls.