On Thu, 2010-11-18 at 21:26 +0800, Wu Fengguang wrote: > On Thu, Nov 18, 2010 at 09:04:34PM +0800, Peter Zijlstra wrote: > > On Wed, 2010-11-17 at 12:27 +0800, Wu Fengguang wrote: > > > - avoid useless (eg. zero pause time) balance_dirty_pages() calls > > > - avoid too small pause time (less than 10ms, which burns CPU power) > > > - avoid too large pause time (more than 100ms, which hurts responsiveness) > > > - avoid big fluctuations of pause times > > > > If you feel like playing with sub-jiffies timeouts (a way to avoid that > > HZ=>100 assumption), the below (totally untested) patch might be of > > help.. > > Assuming there are HZ=10 users. > > - when choosing such a coarse granularity, do they really care about > responsiveness? :) No of course not, they usually care about booting their system,.. I've been told booting Linux on a 10Mhz FPGA is 'fun' :-) > - will the use of hrtimer add a little code size and/or runtime > overheads, and hence hurt the majority HZ=100 users? Yes it will add code and runtime overhead, but it would allow you to have 1ms timeouts even on a HZ=100 system, as opposed to a 10ms minimum. Anyway, I'm not saying you should do it, I just wondered if we had the API, saw we didn't and thought it might be nice to offer it if desired. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
