Re: pipe and af/unix latency differences between aa and jam on smp

From: rwhron@earthlink.net
Date: Tue Jul 09 2002 - 09:05:58 EST


> *Local* Communication latencies in microseconds - smaller is better

> kernel Pipe AF/Unix
> ----------------------------- ------- -------
> 2.4.19-pre7-jam6 29.513 42.369
> 2.4.19-pre8-jam2 7.697 15.274
> 2.4.19-pre8-jam2-nowuos 7.739 14.929

> (last line says that wake-up-sync is not responsible...)

> Main changes between first two were irqbalance and ide6->ide10.

The system is scsi only. pre7-jam6 and pre8-jam2 .config's were
identical.

> Could you try latest -rc1-aa2 ? It includes also irqbalance,

Based on Andrea'a diff logs, irqbalance appeared in 2.4.19pre10aa3.
There are small differences between the pre10-jam2 and aa irqbalance
patches. One new datapoint with pre10-jam3:

*Local* Communication latencies in microseconds - smaller is better
-------------------------------------------------------------------
kernel Pipe AF/Unix
----------------------------- ------- -------
2.4.19-pre10-jam2 7.877 16.699
2.4.19-pre10-jam3 33.133 66.825
2.4.19-pre10-aa2 34.208 62.732
2.4.19-pre10-aa4 33.941 70.216
2.4.19-rc1-aa1-1g-nio 34.989 52.704

A config difference between pre10-jam2 and pre10-jam3 is:
CONFIG_X86_SFENCE=y # pre10-jam2
pre10-jam2 was compiled with -Os and pre10-jam3 with -O2.

> Out of interest, is that a P4/Xeon?

Quad P3/Xeon 700 mhz with 1MB cache.

-- 
Randy Hron
http://home.earthlink.net/~rwhron/kernel/bigbox.html

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