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35a82d1a53
Looks like locking can be optimised quite a lot. Increase lock widths slightly so lo_lock is taken fewer times per request. Also it was quite trivial to cover lo_pending with that lock, and remove the atomic requirement. This also makes memory ordering explicitly correct, which is nice (not that I particularly saw any mem ordering bugs). Test was reading 4 250MB files in parallel on ext2-on-tmpfs filesystem (1K block size, 4K page size). System is 2 socket Xeon with HT (4 thread). intel:/home/npiggin# umount /dev/loop0 ; mount /dev/loop0 /mnt/loop ; /usr/bin/time ./mtloop.sh Before: 0.24user 5.51system 0:02.84elapsed 202%CPU (0avgtext+0avgdata 0maxresident)k 0.19user 5.52system 0:02.88elapsed 198%CPU (0avgtext+0avgdata 0maxresident)k 0.19user 5.57system 0:02.89elapsed 198%CPU (0avgtext+0avgdata 0maxresident)k 0.22user 5.51system 0:02.90elapsed 197%CPU (0avgtext+0avgdata 0maxresident)k 0.19user 5.44system 0:02.91elapsed 193%CPU (0avgtext+0avgdata 0maxresident)k After: 0.07user 2.34system 0:01.68elapsed 143%CPU (0avgtext+0avgdata 0maxresident)k 0.06user 2.37system 0:01.68elapsed 144%CPU (0avgtext+0avgdata 0maxresident)k 0.06user 2.39system 0:01.68elapsed 145%CPU (0avgtext+0avgdata 0maxresident)k 0.06user 2.36system 0:01.68elapsed 144%CPU (0avgtext+0avgdata 0maxresident)k 0.06user 2.42system 0:01.68elapsed 147%CPU (0avgtext+0avgdata 0maxresident)k Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> |
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| .. | ||
| aoe | ||
| paride | ||
| acsi_slm.c | ||
| acsi.c | ||
| amiflop.c | ||
| as-iosched.c | ||
| ataflop.c | ||
| cciss_cmd.h | ||
| cciss_scsi.c | ||
| cciss_scsi.h | ||
| cciss.c | ||
| cciss.h | ||
| cfq-iosched.c | ||
| cpqarray.c | ||
| cpqarray.h | ||
| cryptoloop.c | ||
| DAC960.c | ||
| DAC960.h | ||
| deadline-iosched.c | ||
| elevator.c | ||
| floppy.c | ||
| genhd.c | ||
| ida_cmd.h | ||
| ida_ioctl.h | ||
| ioctl.c | ||
| Kconfig | ||
| Kconfig.iosched | ||
| ll_rw_blk.c | ||
| loop.c | ||
| Makefile | ||
| nbd.c | ||
| noop-iosched.c | ||
| pktcdvd.c | ||
| ps2esdi.c | ||
| rd.c | ||
| scsi_ioctl.c | ||
| smart1,2.h | ||
| swim3.c | ||
| swim_iop.c | ||
| sx8.c | ||
| ub.c | ||
| umem.c | ||
| viodasd.c | ||
| xd.c | ||
| xd.h | ||
| z2ram.c | ||