Re: Poor thread performance on Linux vs. Solaris

On Monday 08 September 2003 5:23 pm, you wrote:

> On Mon, 8 Sep 2003, Bill Soudan wrote:
>
> btw., you seem to have CONFIG_DEBUG_SLAB enabled, right? I'd disable
> it.

I'm running whatever Red Hat's default configuration is.  I'll disable it.

> > c011e270 4046     3.25066     kunmap_atomic
> > c011e1e0 4955     3.98097     kmap_atomic
>
> hm, CONFIG_HIGHPTE enabled?

The help text for HIGHPTE implies it should be enabled on systems with 
large amounts of memory - what's considered a large amount though?  We 
have 4GB on this box.

> > c0138100 24115    19.3746     do_futex
> > c0138bcd 46827    37.622      .text.lock.futex
>
> note that a higher .text.lock.futex count might be natural if multiple
> threads use the _very same_ futex. If there's high contention on that
> lock then it will inevitably cause that contention to show up somewhere
> - on NPTL it will show up as a higher context-switch count and higher
> futex spinlock contention.
>
> btw., what is the total count? It's needed to see the relative overhead
> of futex locking.

Total count from the top of the oprofile results?

Cpu type: P4 / Xeon
Cpu speed was (MHz estimation) : 2785.07
Counter 0 counted GLOBAL_POWER_EVENTS events (time during which processor 
is not
 stopped) with a unit mask of 0x01 (count cycles when processor is active) 
count
 1392500

Bill


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