Re: [NET]: rt_check_expire() can take a long time, add a cond_resched()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Arjan van de Ven <[email protected]>
Date: Thu, 15 Nov 2007 19:38:02 -0800

> On Thu, 15 Nov 2007 04:01:48 GMT
> Linux Kernel Mailing List <[email protected]> wrote:
> 
> >     Using a "if (need_resched())" test before calling
> > "cond_resched();" is necessary to avoid spending too much time doing
> > the resched check. 
> 
> int __sched cond_resched(void)
> {
>         if (need_resched() &&  .....
> 
> somehow I wonder why the second if() is useful at all; it's another
> spot for a branch predictor to miss... and a void function call is
> really really cheap... 

Not by Eric's tests.  Please read the thread, he checked and it's
50ms more expensive to make the function call.

Please, when you notice something interesting in something flying
by on git-web, go check thing out we probably discussed the thing
you're interested in.

And please at least CC: netdev about networking patches, and also the
patch author, which I've corrected in this reply.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux