Date: Fri, 18 Feb 2011 18:36:42 +1030 From: "Daniel O'Connor" <doconnor@gsoft.com.au> To: "Daniel O'Connor" <doconnor@gsoft.com.au> Cc: freebsd-hackers Hackers <freebsd-hackers@freebsd.org> Subject: Re: Scheduler question Message-ID: <5DEC612A-2097-4F2D-A304-77ACA753EF35@gsoft.com.au> In-Reply-To: <53A394ED-7C2E-4E4B-A9A7-CB5F1B27DBE3@gsoft.com.au> References: <53A394ED-7C2E-4E4B-A9A7-CB5F1B27DBE3@gsoft.com.au>
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On 04/02/2011, at 13:26, Daniel O'Connor wrote: > I only have about 10 milliseconds of buffering (96kbyte FIFO, = 8Mbyte/sec) in the hardware, however I have about 128Mb of USB requests = queued up to libusb. hps@ informed me that libusb will only queue = 16kbyte (2msec) in the kernel at one time although I have increased = this. We have upped the hardware FIFO size to 768kb, which is 91msec at = 8Mb/sec, although due to the fact we only start reading out when it's = 1/6th full the effective buffer is 75msec. It does seem much more resilient to CPU load, however heavy disk = activity on the same drive still stalls it for too long :( Given the large buffering in the program it does seem very odd that it = would stall for long enough unless both threads are slept while one is = waiting for disk IO (which seems like a bug to me). BTW I have changed to -current (without WITNESS). -- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C
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