cvs commit: src/sys/cam cam_ccb.h cam_periph.c cam_periph.h
cam_sim.c cam_sim.h cam_xpt.c cam_xpt.h cam_xpt_periph.h src/sys/cam/scsi
scsi_cd.c scsi_ch.c scsi_da.c scsi_low.c scsi_pass.c scsi_pt.c scsi_sa.c
scsi_ses.c scsi_sg.c ...
scottl at samsco.org
Sun Apr 15 23:11:19 UTC 2007
Nate Lawson wrote:
> Amazing work, I owe you a beer for following through where none of us
> did. I see you went with the SIM lock approach, which seems reasonable.
I was surprised when I measured the contention on the SIM lock. It was
much lower than I expected it to be. So this approach is looking to be
pretty good. It can be improved a little bit in CAM, but the focus will
now be on efficient locking strategies for the drivers. I have simple
locking implementations for MPT, AHC, and AHD right now, and I'll have
CISS and maybe SYM shortly. I suspect that the easiest approach to an
efficient strategy will be to make the driver ithreads be a lock-free as
I'm planning on writing a few pages of design docs on this in the next
few days to give people a guide for locking down their drivers.
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