Date: Wed, 27 Nov 2002 14:23:09 +0100 (CET) From: Tomas Pluskal <plusik@pohoda.cz> To: Nick Hibma <n_hibma@van-laarhoven.org> Cc: freebsd-hackers@freebsd.org Subject: umass driver speed Message-ID: <20021127141637.A343-100000@localhost.localdomain> In-Reply-To: <20020824101044.F3912-100000@heather.van-laarhoven.org>
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Hello, It seems to me that the slowness of umass driver is not caused by msdosfs. I know about the msdosfs problems, for example when I run dd from my ZIP drive (with FAT) with request size of 2048, it's extremely slow. When I change request size to 64K, it gains normal speed (about 1MB/s). But with my camera (umass), I get: # dd if=/dev/da0s1 of=/tmp/nikon bs=2048 count=10 10+0 records in 10+0 records out 20480 bytes transferred in 0.379587 secs (53953 bytes/sec) # dd if=/dev/da0s1 of=/tmp/nikon bs=4096 count=10 10+0 records in 10+0 records out 40960 bytes transferred in 0.719477 secs (56930 bytes/sec) # dd if=/dev/da0s1 of=/tmp/nikon bs=8192 count=10 10+0 records in 10+0 records out 81920 bytes transferred in 1.389069 secs (58975 bytes/sec) # dd if=/dev/da0s1 of=/tmp/nikon bs=65536 count=10 10+0 records in 10+0 records out 655360 bytes transferred in 10.832928 secs (60497 bytes/sec) # dd if=/dev/da0s1 of=/tmp/nikon bs=524288 count=1 1+0 records in 1+0 records out 524288 bytes transferred in 8.668605 secs (60481 bytes/sec) The speed is nearly the same, no matter about the request size. What do you think about it ? Tomas On Sat, 24 Aug 2002, Nick Hibma wrote: > > Yes, unfortunately it is a known issue in the msdos file system. The > requests it makes are too small for the driver to take advantage of the > speed of USB. > > Nick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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