On Wed, Mar 05, 2014 at 10:07:35AM +0800, Liu Bo wrote: > Btrfs send reads data from disk and then writes to a stream via pipe or > a file via flush. > > Currently we're going to read each page a time, so every page results > in a disk read, which is not friendly to disks, esp. HDD. Given that, > the performance can be gained by adding readahead for those pages. > > Here is a quick test: > $ btrfs subvolume create send > $ xfs_io -f -c "pwrite 0 1G" send/foobar > $ btrfs subvolume snap -r send ro > $ time "btrfs send ro -f /dev/null" > > w/o w > real 1m37.527s 0m9.097s > user 0m0.122s 0m0.086s > sys 0m53.191s 0m12.857s > > Signed-off-by: Liu Bo <bo.li....@oracle.com>
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