Yes, I am pretty sure you are right about the timing. But it shouldn't be that way. If it is, then there's a bug.
I'm fully willing to accept there is something else I should be doing driver-wise, but it shoudn't require recompiling the stock distribution kernels. Otherwise, Linux is not competitive with Microsoft Windows in this regard! I'll try a recompile and report back. In the meantime, if anyone else has any ideas, please let me know! Gopal ----- Original Message ---- From: Lee Revell <[EMAIL PROTECTED]> To: Open Source <[EMAIL PROTECTED]> Cc: linux-usb-devel@lists.sourceforge.net; linux-kernel@vger.kernel.org Sent: Thursday, October 12, 2006 1:19:12 PM Subject: Re: USB performance bug since kernel 2.6.13 (CRITICAL???) On Thu, 2006-10-12 at 13:05 -0700, Open Source wrote: > Hi, > > Thanks for the rapid response! But...I'm a bit confused. Why is there any > software OS timer involved at all? Bulk messages should be scheduled by the > host controller and for USB 2.0 the microframe period is 125 us. When I > submit an URB, it should be sent to the host controller and scheduled for the > next microframe. When the URB completes I should get an interrupt from the > hardware. Hence, my transactions (WRITE followed by READ) should at worst be > approximately 250 us plus some overhead to process the transaction itself, > provided there aren't any other time consuming processes running on my OS. > My overhead is less than 250 us. I was willing to tolerate 1 ms per > transaction, but 4 ms just doesn't make any sense. Therefore I'm not sure if > CONFIG_HZ is an appropriate excuse for this issue. > I don't know, it just seemed likely because 1ms vs 4ms is close to the change in the timer tick rate. Try it. Lee ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
