Low umass performance with USB 2.0 ports
Eygene A. Ryabinkin
freebsd at rea.mbslab.kiae.ru
Tue Aug 30 12:50:37 GMT 2005
> What is filesystem has your USB drive?
The one I was extensively testing has FAT, but I've checked the UFS2 --
just a bit better -- 1.8 Mb/second. But you're right -- no wdrains at all.
> FreeBSD 4.x had very low performance with FAT filesystem,
> writing process spent lots of time in the wdrain state too.
Yes, it has. But here the same flash drive gives different results for
ehci and uhci devices, and the total speed of echi is lower due to wdrains:
300 Kb/sec versus 500 Kb/sec. And I sometimes write my data to the Windows
partition with FAT to my home HDD -- it has no wdrains. At least, I've not
noticed them. For flash I can.
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