Messages in this thread | | | Date | Sun, 8 Jan 2006 11:54:01 +0100 | From | Willy Tarreau <> | Subject | Re: Why is 2.4.32 four times faster than 2.6.14.6?? |
| |
On Sun, Jan 08, 2006 at 11:23:37AM +0100, Bernd Eckenfels wrote: > Willy Tarreau <willy@w.ods.org> wrote: > > It's rather strange that 2.6 *eats* CPU apparently doing nothing ! > > it eats it in high interrupt load.
*high* ? he never goes far beyond 1000/s !
> And it is caused by the pty-ssh-tcp output,
quite possibly, but I'd rather think it's more precisely related to the ping-pong in the scheduler between grep, cut and ssh. I had the same symptom with 'ls' in xterm with lots of files. It took tens of seconds to list 2000 files while 'ls |cat' gave the same result instantly.
I also have another example (2.6.15-rc5, dual athlon, logged in via SSH) : willy@pcw:willy$ time ls -l
real 0m0.150s user 0m0.016s sys 0m0.024s
Now if I start 4 processes in background : willy@pcw:willy$ time ls -l
real 0m4.432s user 0m0.028s sys 0m0.008s
With 8 processes in background : willy@pcw:willy$ time ls -l
real 0m49.817s user 0m0.020s sys 0m0.008s
willy@pcw:willy$ time ls -l | wc -l 1259
real 0m18.917s user 0m0.016s sys 0m0.012s
I think my case with 4 processes on a dual CPU ressembles Grant's case with 2 processes on single CPU. The background processes are only ones which eat CPU half of their time, which might sometimes match an I/O bound process such as grep from a disk.
> so most likely those are eepro100 interrupts.
I don't think so.
> Gruss > Bernd
Regards, Willy
PS: please don't remove people in CC:
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |