These changes remove unnecessary heap allocations in the XCOPY
READ/WRITE dispatch loop.
Synthetic benchmarks on my laptop using the libiscsi iscsi-dd utility
(--xcopy --max 1 --blocks 65535 src=dst) against a target backed by an 8G
zram (DEBUG_KMEMLEAK=y) iblock backstore (avg across four runs) show:
before: 5.35776G/s
after: 6.12636G/s (approx. +14%)
Feedback appreciated.
Cheers, David
----------------------------------------------------------------
David Disseldorp (5):
scsi: target: use #def for xcopy descriptor len
scsi: target: drop xcopy DISK BLOCK LENGTH debug
scsi: target: avoid per-loop XCOPY buffer allocations
scsi: target: increase XCOPY I/O size
scsi: target: avoid XCOPY per-loop read/write cmd allocations
drivers/target/target_core_xcopy.c | 135 ++++++++++-------------------
drivers/target/target_core_xcopy.h | 14 +--
2 files changed, 57 insertions(+), 92 deletions(-)
