Re: 2.4 vs 2.6 USB mass storage device performance
Alan Stern <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
On Tue, 20 Nov 2007, syed khader wrote: > Hi, > We are evaluating performance of USB on both 2.4.25 > and 2.6.18.2 kernels on an EHCI mass storage device > with a Seagat SCSI device on a Conexant's ARM11 > platform. > We see significant performace difference w.r.t 2.4 > and 2.6 on the same device: > > On 2.6: > #sg_dd /dev/sda dio=1 bs=1M count=100 flag=direct > time=1 > reports 12MBps > while on 2.4 > #sg_dd /dev/sda dio=1 bs=1M count=100 flag=direct > time=1 > reports just 5.1MBps It's good that 2.6 is faster than 2.4 and not slower! :-) > I understand that 2.6 is more capable, but does 2.4 > has any limitations? Are there any patches available > to improve the performance in 2.4? Not exactly limitations. 2.6 has code to speed up large bulk transfers; this code isn't present in 2.4. That probably accounts for much of the speed difference. The code has never been ported back to 2.4, as far as I know. Of course, if you want to do the porting yourself, please feel free. I'll be happy to tell you what needs to be added or changed. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel