Re: big ext3 sequential write improvement in 2.5.51-mm1 gone in 2.5.53-mm1?

From: rwhron@earthlink.net
Date: Thu Jan 23 2003 - 20:26:18 EST


>> >lovely. These two files have perfectly intermingled blocks.

>> Writeback? or read?

> Both.

> The fileystems need fixing....

Did you add a secret sauce to 2.5.59-mm2? 10x sequential
write improvement on ext3 for multiple tiobench threads.

Quad P3 Xeon (4GB ram)
8 GB files
4K blocksize
32 threads
Rate = MB/sec
latency in milliseconds

Sequential Writes ext3
                              Avg Maximum Lat% Lat% CPU
Kernel Rate (CPU%) Latency Latency >2s >10s Eff
---------- ------------------------------------------------------------
2.4.20aa1 11.85 72.77% 11.814 21802.73 0.05036 0.00000 16
2.5.59 3.42 17.36% 83.976 3109518.52 0.11253 0.05088 20
2.5.59-mm2 32.39 34.28% 7.742 340597.62 0.04287 0.01765 94

Similar improvement for seq writes for 2, 4, 8, 16, 64, 128, 256 threads.

Sequential reads on ext3 with 2.5.59-mm2 improves around 3x for various
thread counts. Below is 32 threads.

Sequential Reads ext3
                              Avg Maximum Lat% Lat% CPU
Kernel Rate (CPU%) Latency Latency >2s >10s Eff
---------- ------------------------------------------------------------
2.4.20aa1 8.24 7.21% 28.587 449134.11 0.10395 0.07086 114
2.5.59 9.50 5.50% 36.703 4310.62 0.00000 0.00000 173
2.5.59-mm2 35.28 17.69% 10.173 18950.56 0.01010 0.00000 199

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

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