[Bug 30557] Re: cpu idle time in /proc/stat wrong

[Brian Eaton]

Well, my problem goes away if I change my config from CONFIG_HZ_250 to
CONFIG_HZ_1000.  The change from 1000 to 250 was done in 2.5.15-24,
which corresponds nicely to when I started to see problems with sluggish
performance.

  * i386/amd64: Change HZ=1000 to HZ=250. The high frequency was causing high
    power consumption on some laptops, and also some latency under certain I/O
    loads.

Even when I rebuild with CONFIG_HZ_1000, the idle time in /proc/stat
continues to go up very slowly.  Seems more and more likely we're
talking about different problems.

Nonetheless, I'd much prefer it if the ubuntu 686 kernel didn't hose X
performance on my laptop.  I doubt regressing the "HZ=250" change would
count as progress, but if anyone has suggestions for further research
into why HZ=250 causes problems on my machine, I'd be interested in
hearing them.

I'd also be interested whether anybody else reporting issues sees a
change when HZ is set to 1000 instead of 250.

-- 
cpu idle time in /proc/stat wrong
https://launchpad.net/bugs/30557