Re: [RFC] block layer support for DMA IOMMU bypass mode II

From: Grant Grundler (grundler@parisc-linux.org)
Date: Tue Jul 29 2003 - 23:42:56 EST


On Mon, Jul 28, 2003 at 01:15:13PM +0200, Andi Kleen wrote:
> Run it with 100-500 users (reaim -f workfile... -s 100 -e 500 -i 100)

jejb was wondering if 4k pages would cause different behaviors becuase
of file system vs page size (4k vs 16k). ia64 uses 16k by default.
I've rebuilt the kernel with 4k page size and VMERGE != 0.
The substantially worse performance feels like a rat hole because
of 4x pressure on CPU TLB.

Ideally, we need a workload to test BIO code without a file system.
Any suggestions?

grant

iota:/mnt# reaim -f /mnt/usr/local/share/reaim/workfile.new_dbase -s100 -e 500 -i 100
REAIM Workload
Times are in seconds - Child times from tms.cstime and tms.cutime

Num Parent Child Child Jobs per Jobs/min/ Std_dev Std_dev JTI
Forked Time SysTime UTime Minute Child Time Percent
100 118.90 21.17 214.03 5197.78 51.98 4.52 3.98 96
200 236.75 42.54 429.94 5220.63 26.10 9.43 4.16 95
300 354.94 64.47 644.80 5223.34 17.41 14.47 4.27 95
400 474.50 87.01 861.09 5209.66 13.02 24.76 5.59 94
500 594.26 109.80 1077.00 5199.78 10.40 25.36 4.49 95
Max Jobs per Minute 5223.34
iota:/mnt#

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