Re: [RFC][PATCH] O(1) Entitlement Based Scheduler

From: Timothy Miller
Date: Wed Feb 25 2004 - 12:01:03 EST




John Lee wrote:

X Windows Performance
=====================

The X server isn't strictly an interactive process, but it does have a major
influence on interactive response. The fact that it services a large number
of clients means that its CPU usage rate can be quite high, and this negates the above mentioned favourable treatment of interactive and I/O bound processes.

Therefore, for best interactive feel, it is recommended that the X server run with a nice value of at least -15. From my own testing, doing a window wiggle test with a make -j16 in the background and X reniced was slightly better than for the stock kernel.

When running apps such as xmms, I recommend that they should be reniced as well
when the background load is high. With the above setup and xmms reniced to -9,
there were no sound skips at all (without renicing, a few skips could be
detected).


Well, considering that X is suid root, it's okay to require that it be run at nice -15, but how is the user without root access going to renice xmms? Even for those who do, they're not going to want to have to renice xmms every time they run it. Furthermore, it seems like a bad idea to keep marking more and more programs as suid root just so that they can boost their priority.

Not to say that your idea is bad... in fact, it may be a pipe dream to get "flawless" interactivity without explicitly marking which programs have to be boosted in priority. Still, Nick and Con have done a wonderful job at getting close.

This is a tough problem.

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