Date: Tue, 30 Aug 2005 20:34:05 +0800 From: Eugene Grosbein <eugen@kuzbass.ru> To: "Eygene A. Ryabinkin" <freebsd@rea.mbslab.kiae.ru> Cc: hackers@freebsd.org, freebsd-usb@freebsd.org Subject: Re: Low umass performance with USB 2.0 ports Message-ID: <4314523D.79926C81@kuzbass.ru> References: <20050830092818.GD881@rea.mbslab.kiae.ru>
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"Eygene A. Ryabinkin" wrote: > > Good day. > I am observing very low umass performance: when I am trying to move a large > file from/to my USB 2.0 flash that is plugged into the USB 2.0 port: transfer > starts fine at 3.5 Mb/sec, but after some 20 Mbytes it hangs and the process > (dd) stay in the wdrain state. The activity LED on the flash shows no activity. > Operations do continue, but very slow and the most time of the copying process > spends in the wdrain state. All attempts to invoke `sync` or to see the > file state via `ls` are hanging until `dd` leaves the wdrain state. > It does not matter what flash is used: I tried Apacer and the Kingmax ones -- > the result is the same. > If I plug the flash into the USB 1.1 port and trying to move some data -- it > works fine, no hangs. Speed is 500 Kb/sec. What is filesystem has your USB drive? FreeBSD 4.x had very low performance with FAT filesystem, writing process spent lots of time in the wdrain state too. Eugene
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