[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

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


STATEMENT OF CONFIDENTIALITY

The information contained in this electronic message and any attachments
to this message are intended for the exclusive use of the addressee(s)
and may contain confidential or privileged information. If you are not
the intended recipient, please notify SunGard Trading Systems immediately
at (201) 499-5900 and destroy all copies of this message and any
attachments.




[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]