[time-nuts] Lady Heather Overhead
David C. Partridge
david.partridge at dsl.pipex.com
Sun Jan 3 15:29:49 UTC 2010
It polls the serial port continually :-(
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Steve Rooke
Sent: 03 January 2010 12:00
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lady Heather Overhead
Well, it then looks like it is going through this rapid loop of giving up
processing power and asking for it again immediately, and on my system there
is plenty of spare capacity so it gets its thread back again. Perhaps this
is what is generating all the masses of system calls as the balance between
user and system processing is all wrong.
Does the code not indicate that it needs CPU via waits, real sleeps or
interrupts on I/O and the like. Just believing that the system it is running
on is solely dedicated to it seems a little strange to me but then I come
from a multitasking background where we learn to share, and have CPU idle
2010/1/1 Mark Sims <holrum at hotmail.com>:
> An idle Windows machine allocates 50% of its resources to a task when it
starts up. This shows up as 50% CPU utilization. A second Heather will
show as around 100% total utilization (50 % each). These usage numbers are
> Heather VERY periodically returns it's time slot to the system with the
flag that says, "Hey, if you aren't doing anything else, I'd kinda like
that time back.". So if you bring up four Heathers, each will then show
25% utilization, etc. I have seen a dozen Heathers running on a fairly
slow machine (and quite a sight it is).
> Basically all the Heathers soak up all the free time on the system and
share it amongst themselves. The program runs just fine on a 100 MHz WIN98
laptop. If you are actually using a full core, you have other problems...
> There is a recently added command line flag (/tw=msecs) that says to force
Sleep(msecs) calls in place of Sleep(0) calls. It slows the system response
time down, but might be useful for power saving on laptops, etc.
> Mark John
> from a nut post:
>> do know that
> there is a fair amount of processor load, including a lot of system
> calls. On my system, running LH under wine takes the equivalent of 1
> on my quad core.
> I'm sure not new to you and I hardly know what I'm talking about BUT
> what I have noticed is:
> MY LadyHeather programs
> will take all the spare windows processor time available even on my
> fastest windows XT machine.
> And then again I have no trouble running at least four simultaneous LH
> programs (even different versions) all at the same time on a slow
> machine, so they don't need much, they'll just take whatever is
> available, but they seem to share well.
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Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is; A man with two clocks is never
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