Re: USB Storage speed regression since 2.6.12

[Brice Goglin]

Le 01.09.2005 13:36, DervishD a écrit :
>     I don't know if this is a known issue, but usb-storage speed for
> 'Full speed' devices dropped from 2.6.11.12 (more than 800Kb/s) to
> 2.6.12 (less than 250Kb/s). The problem still exists in 2.6.13.
> 
>     The lack of speed seems to affect only the OHCI driver. My test
> was done over a PCI USB 2.0 card, ALi chipset, OHCI driver (well
> EHCI+OHCI) and using a full speed device capable of 12MBps. The
> average measured speeds are:
> 
>     - 2.4.31:           about 450Kb/seg
>     - 2.6.11-Debian:    about 800Kb/seg
>     - 2.6.11.12:        about 820Kb/seg
>     - 2.6.12.x:         about 200Kb/seg
>     - 2.6.13:           about 200Kb/seg

Are you mounting this storage with vfat and 'sync' option ?
IIRC, sync support for vfat was added around 2.6.12, making
write way slower since it's now really synchron.

Brice
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