Re: Why i lost speed in transplant driver from 2.4 to 2.6 ?

Alan Stern <[email protected]>
Newsgroups gmane.linux.usb.devel
Message-ID <[email protected]>
On Tue, 27 Mar 2007, DuRui wrote:

> Hello everybody 
> 	
> 	I have creat 3 endpiont, which one for intrrupt in, one for bulk in, and the third for bluk out. my driver could reach the transport rate at 20MB/s in 2.4 version kernel. but in 2.6 version i only got a half, 10MB/s. the same mechanism 
> been used to implement driver. i confuse about it. it should faster in 2.6 kernel.
>     the data mainly from host to target, and the intrrupt in recive some data from target every 2 milliseconds.driver use a queue to submit bulk out urb, could submit 32 urb each time. and the urb buffer is 16KB, and the intrrupt urb is submit in intrrupt callback function. when intrrupt endpiont is disable, the data rate from host to target may gain about 2 Mbytes.
> kmalloc is used to allocate urb buf.  
>     which aspect should take care to transplant driver from 2.4 to 2.6, and how to optimize the usb speed?
> 	Any comments will be appreciate !

It's possible that your driver is affected by the HZ setting.  If you set 
CONFIG_HZ_1000 in 2.6, perhaps the throughput will improve.

Alan Stern


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