Re: VST and Sched Load Balance

[Srivatsa Vaddagiri <vatsa@in.ibm.com>]

On Tue, Apr 19, 2005 at 09:07:49AM -0700, Nish Aravamudan wrote:
> > +                       if (jiffies - sd1->last_balance >= interval) {


> Sorry for the late reply, but shouldn't this jiffies comparison be
> done with time_after() or time_before()?

I think it is not needed. The check should be able to handle overflow case also.

This probably assumes that you don't sleep longer than (2e32 - 1) jiffies
(which is ~1193 hrs). Current VST implementation let us sleep way less than that
limit (~896 ms) since it uses 32-bit number for sampling TSC. When it is
upgraded to use 64-bit number, we may have to ensure that this limit (1193 hrs)
is not exceeded.

-- 


Thanks and Regards,
Srivatsa Vaddagiri,
Linux Technology Center,
IBM Software Labs,
Bangalore, INDIA - 560017