Messages in this thread | | | Date | Wed, 05 Mar 2003 15:00:23 -0800 | From | Janet Morgan <> | Subject | Re: [RFC][Patch] Retry based aio read for filesystems |
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Suparna Bhattacharya wrote:
> For the last few days I've been playing with prototyping > a particular flavour of a retry based implementation for > filesystem aio read.
Hi Suparna,
I ran an aio-enabled version of fsx on your patches and no errors were reported. I plan on using gcov to determine the test coverage I obtained.
I also did a quick performance test using wall time to compare sync and async read operations with your patches applied. For the sync case I ran 10 processes in parallel, each reading 1GB in 1MB chunks from a per-process dedicated device. I compared that to a single aio process iteratively calling io_submit/io_getevents for up to 10 iocbs/events where each iocb specified a 1MB read to its dedicated device until 1GB was read. Whew!
The result was that wall time for the sync and async testcases were consistently identical, i.e., 1m30s:
# sync_test start time: Wed Mar 5 14:02:05 PST 2003 end time: Wed Mar 5 14:03:35 PST 2003
# aio_test start time: Wed Mar 5 13:52:04 PST 2003 end time: Wed Mar 5 13:53:34 PST 2003
syncio vmstat: procs memory swap io system cpu r b w swpd free buff cache si so bi bo in cs us sy id 4 6 2 3324 3888 11356 3668848 0 0 151296 0 2216 2395 0 100 0 4 6 1 3324 3888 11368 3668820 0 0 151744 5 2216 2368 0 100 0 1 9 1 3324 3952 11368 3668860 0 0 151209 1 2213 2356 0 100 0 5 5 1 3324 3940 11344 3668864 0 2 148948 3 2215 2387 0 100 0 1 9 1 3348 3936 11264 3668968 0 6 150767 7 2209 2345 0 100 0 6 4 1 3480 3920 11192 3669364 0 33 151456 33 2218 2340 0 100 0 4 6 2 3568 3896 11316 3669352 0 21 151887 21 2218 2385 0 100 0 7 3 1 3704 3820 11364 3669428 31 34 148687 35 2222 2344 1 99 0
aio vmstat: procs memory swap io system cpu r b w swpd free buff cache si so bi bo in cs us sy id 2 0 1 4016 4040 11192 3669644 0 17 133152 25 2073 502 0 40 60 1 0 1 4016 4104 11196 3669716 0 0 132288 1 2073 537 0 40 60 2 0 2 4016 4104 11196 3669764 0 0 132416 0 2067 511 0 40 60 1 0 1 4016 4104 11200 3669788 0 0 133088 1 2075 523 0 41 59 1 0 1 4016 5576 11200 3668240 0 0 132384 0 2066 526 0 40 60 1 0 1 4036 4092 11200 3669756 0 5 135116 5 2094 492 0 46 54 1 0 1 4180 4016 11192 3669944 0 36 135968 40 2111 499 0 46 54 2 0 2 4180 4060 11176 3669832 0 0 137152 0 2119 463 1 46 53 1 0 1 4180 7060 11180 3666980 0 0 136384 2 2107 498 0 44 56
-Janet
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