Hi. I wrote a patch that adds blk_run_backing_dev on page_cache_async_readahead so readahead I/O is unpluged to improve throughput. Following is the test result with dd. #dd if=testdir/testfile of=/dev/null bs=16384 -2.6.30-rc6 1048576+0 records in 1048576+0 records out 17179869184 bytes (17 GB) copied, 224.182 seconds, 76.6 MB/s -2.6.30-rc6-patched 1048576+0 records in 1048576+0 records out 17179869184 bytes (17 GB) copied, 206.465 seconds, 83.2 MB/s Sequential read performance on a big file was improved. Please merge my patch. Thanks. Signed-off-by: Hisashi Hifumi <hifumi.hisashi@xxxxxxxxxxxxx> diff -Nrup linux-2.6.30-rc6.org/mm/readahead.c linux-2.6.30-rc6.unplug/mm/readahead.c --- linux-2.6.30-rc6.org/mm/readahead.c 2009-05-18 10:46:15.000000000 +0900 +++ linux-2.6.30-rc6.unplug/mm/readahead.c 2009-05-18 13:00:42.000000000 +0900 @@ -490,5 +490,7 @@ page_cache_async_readahead(struct addres /* do read-ahead */ ondemand_readahead(mapping, ra, filp, true, offset, req_size); + + blk_run_backing_dev(mapping->backing_dev_info, NULL); } EXPORT_SYMBOL_GPL(page_cache_async_readahead); -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
