Subject: Re: loaded router, excessive getnstimeofday in oprofile

From: Stephen Hemminger <[email-masked]>
Date: Fri, 29 Aug 2008 08:43:18 -0700

On Thu, 28 Aug 2008 22:55:29 +0300
Denys Fedoryshchenko <[email-masked]> wrote:

> On Thursday 28 August 2008, Eric Dumazet wrote:
> > OK, please try oprofile with call graph analysis.
> I did already. Even because most of programs (except ripd/zebra) can be 
> killed, and i kill them, it doesn't change almost anything.
> 
> it seems heavy things causing instability:
> 
> 1)HTB (resolution can be lowered to improve performance, i will try Jarek 
> patch soon)

If you are doing HTB it also calls clock to get timing information.
Each packet dequeue in htb calls psched_get_time() and that becomes
another call nano-second real time clock.

If your embedded processor has really expensive clock, you probably
just want to provide an alternative cheaper time source with less
resolution.