Date: Thu, 5 Apr 2012 05:22:46 +0200 From: Alexander Leidinger <Alexander@Leidinger.net> To: Jerry Toung <jrytoung@gmail.com> Cc: freebsd-hackers <freebsd-hackers@freebsd.org> Subject: Re: CAM disk I/O starvation Message-ID: <20120405052246.00002c53@unknown> In-Reply-To: <CADC0LVm1HY2Dz%2BVk_GK35szRS6ySviLhMiL1TSRBOnPwQnBwRg@mail.gmail.com> References: <CADC0LV=-e%2B7PshRQdc69e2-Vktf6XFpVrqiMpx=QL4m_%2B9hSnw@mail.gmail.com> <20120403193124.46ad9de9@ernst.jennejohn.org> <CADC0LVm1HY2Dz%2BVk_GK35szRS6ySviLhMiL1TSRBOnPwQnBwRg@mail.gmail.com>
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On Tue, 3 Apr 2012 14:27:43 -0700 Jerry Toung <jrytoung@gmail.com> wrote: > On 4/3/12, Gary Jennejohn <gljennjohn@googlemail.com> wrote: > > > It would be interesting to see your patch. I always run HEAD but > > maybe I could use it as a base for my own mods/tests. > > > > Here is the patch This looks fair if all your disks are working at the same time (e.g. RAID only setup), but if you have a setup where you have multiple disks and only one is doing something, you limit the amount of tags which can be used. No idea what kind of performance impact this would have. What about the case where you have more disks than tags? I also noticed that you do a strncmp for "da". What about "ada" (available in 9 and 10), I would assume it suffers from the same problem. Bye, Alexander. -- http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID = B0063FE7 http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID = 72077137
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