Large read I/O will be typical in some use cases such as
web stream services. On the other hand, large write I/O
may not be typical but will be sufficiently probable.
Currently when large I/O is submitted to the RAID bdev,
the I/O will be divided by the strip size of it and then
divided I/Os are submitted sequentially.
This patch tries to improve the performance of the RAID bdev
in large I/Os. Besides, when the RAID bdev supports higher
levels of RAID (such as RAID5), it should issue multiple
I/Os to multiple base bdevs by batch fasion in the parity
update. Having experience in batched I/O will be helpful
in the future case too.
In this patch, submit split I/Os by batch until all child IOVs
are consumed or all data are submitted. If all child IOVs are
consumed before all data are submitted, wait until all batched
split I/Os complete and then submit again.
In this patch, test code is added too.
Change-Id: If6cd81cc0c306e3875a93c39dbe4288723b78937
Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-on: https://review.gerrithub.io/424770
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Chandler-Test-Pool: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
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