Robert M. Hyatt wrote:
>
> On Fri, 29 Jan 1999, Neil Conway wrote:
> > I find that running a code under X instead of in a VT can make a huge
> > difference for good or for bad (like tens of percent). This is
> > surprising to me.
>
> I only see this on graphics chipsets that are sloppy about how 'scrolling'
> is handled. IE I have a trident chipset on my notebook and if I run a
> compute bound task on that machine, but it produces a modest amount of
> output that causes scrolling, then xwindows eats a significant amount of
> cpu time, easily hitting 20% of total, sometimes higher...
No, I really was talking about CPU-bound stuff - negligible level of
I/O.
The behaviour is equally likely to change if I run the code under bash
instead of tcsh - sometimes bash runs it quicker (and REPEATABLY QUICKER
I mean, not once) and sometimes tcsh runs it quicker. The behaviour
stays the same for a while until something in the innards of the machine
(memory-mapping?) changes and then the speed-changing can either invert
polarity or disappear for a while... Quite often when it disappears I'm
left with repeated runs giving me the LOWER speed which is a shame.
I have never had time to track it down though...
Neil
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