Date: Wed, 27 Nov 2002 15:51:54 +0100 (CET) From: Nick Hibma <n_hibma@van-laarhoven.org> To: Tomas Pluskal <plusik@pohoda.cz> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: Re: umass driver speed Message-ID: <20021127155133.W99600-100000@uitsmijter.van-laarhoven.org> In-Reply-To: <20021127141637.A343-100000@localhost.localdomain>
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The ZIP Drive is USB as well? Are you using a UHCI controller (dmesg)? Nick > > 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 > > -- n_hibma@van-laarhoven.org http://www.van-laarhoven.org/ n_hibma@FreeBSD.org http://www.etla.net/~n_hibma/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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