Messages in this thread | | | Date | Mon, 4 Feb 2002 01:32:14 +0100 (CET) | From | Ingo Molnar <> | Subject | Re: Short question regarding generic_make_request() |
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On Sun, 3 Feb 2002, Steffen Persvold wrote:
> Ok, the reason I'm asking is that I receive a request from a remote > machine on interrupt level (tasklet) and want to submit this to the > local device. The reason I'm using a tasklet instead of a kernel > thread is that somewhere between RedHat's 2.4.3-12 and 2.4.9-12 > kernels the latency of waking up a kernel thread increased (using a > semaphore method similar to the one used in loop.c). I don't know why > this happened, but I guess that if I still could use a kernel thread > there wouldn't be any problems using generic_make_request().
you really want a kernel thread for this. The wakeup latency of a kernel thread is on the order of 2-3 usecs (context switch overhead included), nothing compared to usual block IO costs.
you say that the latency of waking up a kernel thread has increased - by how much?
Ingo
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