Messages in this thread | | | Date | Tue, 24 Feb 2004 21:33:41 +0530 | From | Suparna Bhattacharya <> | Subject | Latest AIO patchset |
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The latest set of AIO patches are being maintained at: http://www.kernel.org/pub/linux/kernel/people/suparna/aio/
The patches have been reduced to a minimal set that addresses the most relevant blocking points. Please let me know if you think there is a case for bringing in any of the additional patches. (The patches need to be applied in the order mention in the 'series' file)
A new addition to the patchset is Chris Mason's nice and simple implementation of AIO support for pipes using the retry infrastructure. He also fixed some problems in the AIO cancel logic to make it play well with retries.
Besides this and some re-organization and cleaning up, there are a couple of changes since the last set of patches in -mm, that are worth a mention:
- Upfront readahead is now clipped to the readahead limit for the device (ra_pages) and happens only for AIO. This helps address the sendfile regression seen by Felix von Leitner. If your AIO read requests are likely to exceed the default readahead size, then use hdparm -a <new size> to tune it. The patchset also currently includes Ram Pai's adaptive lazy readahead code which is required for good streaming AIO read performance. - David Brownell's suggestion of enabling the fops to set up their own retry methods. This should make his USB gadgetfs AIO patch co-exist smoothly with fsaio.
Some basic results are up comparing streaming non-cached random AIO read/write throughputs for a single ext3 file using aio-stress for various io sizes with and without these patches, and also comparsions with O_DIRECT AIO throughputs. The short summary has been a doubling of throughput using the fsaio patches, which is also close to the results seen with O_DIRECT AIO.
As usual feedback, bug fixes, test results etc are welcome.
Regards Suparna
-- Suparna Bhattacharya (suparna@in.ibm.com) Linux Technology Center IBM Software Lab, India
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