On Thu, Nov 30, 2006 at 09:07:42PM +1100, Nick Piggin (nickpiggin@yahoo.com.au) wrote:

quoted

Doesn't the provided solution is just a in-kernel variant of the
SCHED_FIFO set from userspace? Why kernel should be able to mark some
users as having higher priority?
What if workload of the system is targeted to not the maximum TCP
performance, but maximum other-task performance, which will be broken
with provided patch.

David's line of thinking for a solution sounds better to me. This patch
does not prevent the process from being preempted (for potentially a long
time), by any means.

It steals timeslices from other processes to complete tcp_recvmsg()
task, and only when it does it for too long, it will be preempted.
Processing backlog queue on behalf of need_resched() will break fairness
too - processing itself can take a lot of time, so process can be
scheduled away in that part too.

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