Messages in this thread | | | Date | Mon, 22 Sep 2008 01:18:37 -0400 | From | George Nychis <> | Subject | printing current system time from kernel space |
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Hi all,
Please CC me on any responses.
I am looking to measure the latency of USB data between kernel space and user space. The user space driver uses a URB to get data from the device to the kernel and finally to user space.
To measure this latency, I was thinking of printing the current system time when a read occurs/succeeds in drivers/usb/core/devio.c at the function usbdev_read(), and then again in user space when the URB succeeds in reading. Then, I could subtract the two times to get the latency.
I spent some time googling, but could not find out how or if it is possible to read the current system time in kernel space. I could insert a printk() somewhere in usbdev_read() then.
If it is not possible to read the current system time, is there some other shared clock between kernel and user space that I could use for this?
Thank you! George
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