On Mon, May 02, 2011 at 02:02:34PM -0700, Abu Rasheda wrote:
On Mon, May 2, 2011 at 12:28 PM, Greg KH <greg@kroah.com> wrote:
On Mon, May 02, 2011 at 11:32:32AM -0700, Abu Rasheda wrote:
I am testing my driver on much faster host processor and facing following issues:
My host is too powerful and it can fill up device buffer queue very fast.
What kind of device is this?
its a networking device
It sounds like a broken device, you need to be able to handle large data streams, right? Are you running Linux in this device and that is the issue you are having?
I get best performance when I do busy wait, but this is not desirable and is bad design.
I need to sleep and wake up quickly and predictability. Indication from device that queue has space, is coming in form of memory write (device writes to a memory location of i86 processor).
I tried using wait_event_interruptible_timeout, I am depending on 2nd parameter of the function but it wake up is too slow, even tried using value of 1.
Why not try increasing the buffer in your driver to handle any amount of data needed?
Problem come from the fact that remote end can be slow, so device / driver cannot do much. If I increase buffer size, than running on (even) faster host processor will bring back same issue. I am looking for solution which will scale.
I check for available buffer size if space is low, I sleep and retry. This is causing lot of CPU to be wasted.
How can I optimize this ?
Use NAPI for your network driver? good luck, greg k-h