Re: [PATCH] Staircase scheduler v7.4
From: Peter Williams
Date: Mon Jun 28 2004 - 18:22:37 EST
Nick Piggin wrote:
Felipe Alfaro Solana wrote:
I have tested 2.6.7-bk10 plus from_2.6.7_to_staircase_7.7 patch and,
while it's definitively better than previous versions, it still feels a
little jerky when moving windows in X11 wrt to -mm3. Renicing makes it a
little bit smoother, but not as much as -mm3 without renicing.
You know, if renicing X makes it smoother, then that is a good thing
IMO. X needs large amounts of CPU and low latency in order to get
good interactivity, which is something the scheduler shouldn't give
to a process unless it is told to.
I agree. Although the X servers CPU usage is usually relatively low
(less than 5%) it does have periods when it can get quite high (greater
than 80%) for reasonably long periods. This makes it difficult to come
up with a set of rules for CPU allocation that makes sure the X server
gets what it needs (when it needs it) without running the risk of giving
other tasks with similar load patterns unnecessary and unintentional
preferential treatment.
However, I think that there is still a need for automatic boosts for
some tasks. For instance, programs such as xmms and other media
streamers are ones whose performance could worsen as a result of the X
server being reniced unless it is treated specially and the boost they
are given needs to be enough to put them before the X server in priority
order. But renicing X would enable a tightening of the rules that
govern the automatic dispensing of preferential treatment to tasks that
are perceived to be interactive which should be good for overall system
performance.
Peter
--
Peter Williams pwil3058@xxxxxxxxxxxxxx
"Learning, n. The kind of ignorance distinguishing the studious."
-- Ambrose Bierce
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