Date: Sun, 15 Apr 2007 17:10:53 -0600 From: Scott Long <scottl@samsco.org> To: Nate Lawson <nate@root.org> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, Scott Long <scottl@FreeBSD.org>, cvs-all@FreeBSD.org Subject: Re: 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 ... Message-ID: <4622B0FD.9000400@samsco.org> In-Reply-To: <462260B7.8090602@root.org> References: <20070415084926.C77C816A521@hub.freebsd.org> <462260B7.8090602@root.org>
next in thread | previous in thread | raw e-mail | index | archive | help
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 possible. 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. Scott
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4622B0FD.9000400>