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authorTony Battersby <tonyb@cybernetics.com>2007-11-09 13:04:35 -0500
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-01-11 18:22:42 -0600
commit1e6c38cec08f88b0df88a34e80f15492cace74e9 (patch)
tree9d477b95a05f9a4552da19429da0265878d7deba /crypto/des_generic.c
parent8ee24023ef43c77cdaea1add00e1e45cc4fc3261 (diff)
[SCSI] 3w-9xxx: fix abysmal write performance on some motherboards
The 3ware 9500S-8 SATA RAID controller exhibits terrible write performance when PCI memory-write-and-invalidate is disabled. This is easy to demonstrate by replacing pci_try_set_mwi() in the patch below with pci_clear_mwi(). My benchmarks show the following: MWI disabled: 15 MB/s write, 330 MB/s read MWI enabled: 240 MB/s write, 330 MB/s read Most motherboards will enable MWI without the driver having to set it explicitly, so most people probably wouldn't encounter this problem. For the few motherboards that don't enable it, this patch could give a 16x performance improvement for writing. This issue does not seem to affect the 9550SX controller, but the patch doesn't hurt it either. I haven't tested any of the other 3ware controllers. Signed-off-by: Tony Battersby <tonyb@cybernetics.com> Acked-by: adam radford <aradford@gmail.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'crypto/des_generic.c')
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