Date: Tue, 8 Feb 2011 00:14:23 +1030 From: "Daniel O'Connor" <doconnor@gsoft.com.au> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-hackers@freebsd.org Subject: Re: Scheduler question Message-ID: <88A9D148-7E3C-4ADB-90FC-B95C4D3BBD2E@gsoft.com.au> In-Reply-To: <AANLkTikbPsF9d3GTDj0JtrLL%2BML=3_f1ShU0e5H7hYEM@mail.gmail.com> References: <53A394ED-7C2E-4E4B-A9A7-CB5F1B27DBE3@gsoft.com.au> <iignas$kbc$1@dough.gmane.org> <AA0DA14A-A8E5-48C5-AABE-ECCB02C59D19@gsoft.com.au> <iii67s$ngs$1@dough.gmane.org> <7108E013-77D1-47F8-892E-5027DB7D432B@gsoft.com.au> <990005CD-39BD-45F6-BD07-ACEE79DF5A03@gsoft.com.au> <AANLkTincOBWKhr9qWX_dFmukWeUCG61aYT0AXd-VYYTu@mail.gmail.com> <772B352C-7241-4326-8B49-3FB675896609@gsoft.com.au> <AANLkTik_kxCgtjTBshEc4zF5X%2BSKV6L1R4waYyLeM_r3@mail.gmail.com> <71549325-5FD1-4516-B49E-098AFBEFE8B7@gsoft.com.au> <AANLkTikbPsF9d3GTDj0JtrLL%2BML=3_f1ShU0e5H7hYEM@mail.gmail.com>
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On 07/02/2011, at 23:36, Ivan Voras wrote: >> OK, I wrote the data to /dev/null from USB and ran diskutil in a loop = and it doesn't drop out. >=20 > Maybe I misunderstood you and it's a different problem than what I was > experiencing; is this a better description of your problem: >=20 > 1) you have a program communicating with a USB device > 2) it reads from the device and writes to a file > 3) you experience stalls when you write the data recived from the USB > device to the file but only if the file system you're writing on is > also loaded by something else - heavy reads? >=20 > ? Yes, however CPU loading also seems to affect it. Unfortunately I don't have a useful measurement to show the problem - ie = I don't have a metric which correlates with the hardware FIFO filling = up. This makes the testing rather annoying :) -- 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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