Messages in this thread | | | Subject | Re: RFC on io-stalls patch | From | Chris Mason <> | Date | 15 Jul 2003 05:12:28 -0400 |
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On Tue, 2003-07-15 at 04:28, Jens Axboe wrote:
> Definitely, because prepare to be a bit disappointed. Here are scores > that include 2.4.21 as well:
> io_load: > Kernel [runs] Time CPU% Loads LCPU% Ratio > 2.4.21 3 543 49.7 100.4 19.0 4.08 > 2.4.22-pre5 3 637 42.5 120.2 18.5 4.75 > 2.4.22-pre5-axboe 3 540 50.0 103.0 18.1 4.06
Huh, this is completely different than io_load on my box (2P scsi, ext3, data=writeback)
io_load: Kernel [runs] Time CPU% Loads LCPU% Ratio 2.4.21 3 520 52.5 27.8 15.2 3.80 2.4.22-pre5 3 394 69.0 21.5 15.4 2.90 2.4.22-sync 3 321 84.7 16.2 15.8 2.36
Where 2.4.22-sync was the variant I posted yesterday. I don't really see how 2.4.21 can get numbers as good as 2.4.22-pre5 on the io_load test, the read starvation with a big streaming io is horrible.
The data=writeback is changing the workload significantly, I used it because I didn't want the data=ordered code to flush all dirty buffers every 5 seconds. I would expect ext3 data=ordered to be pretty starvation prone in 2.4.21 as well though.
BTW, the contest run times vary pretty wildy. My 3 compiles with io_load running on 2.4.21 were 603s, 443s and 515s. This doesn't make the average of the 3 numbers invalid, but we need a more stable metric.
-chris
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