Optimal function choice


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Profile BilBg
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Message 719730 - Posted: 29 Feb 2008, 4:12:41 UTC



1. During "Optimal function choice" by setiathome_enhanced 5.27
if I start some heavy task (e.g. game) in the middle of this process will this affect it?

(the functions executed when "heavy task" is running will take longer -
will this fool the setiathome_enhanced 5.27 that they are not optimal)


2. Is there any function of "Optimal function choice" group that uses (tries) 3DNow! ?

(As you know the older AMD processors - K6-2 ... early Athlons/Durons - do not have SSE)
(On K6-2+ everytime FPU is choosen)


Profile Mark Peters
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Message 720533 - Posted: 1 Mar 2008, 23:27:02 UTC - in response to Message 719730.



1. During "Optimal function choice" by setiathome_enhanced 5.27
if I start some heavy task (e.g. game) in the middle of this process will this affect it?

(the functions executed when "heavy task" is running will take longer -
will this fool the setiathome_enhanced 5.27 that they are not optimal)


2. Is there any function of "Optimal function choice" group that uses (tries) 3DNow! ?

(As you know the older AMD processors - K6-2 ... early Athlons/Durons - do not have SSE)
(On K6-2+ everytime FPU is choosen)

I think it depends on what setting you have configured Boinc, is your setup always on WU load en 100%, than your CPU will divide the task in 2, your game and Boinc. If you got 2 CPU's than you 'll never have a problem. I did have, still do, a K6 AMD and when I played games local, SETI will be online on the background, never had a problem, only when I went online (game of UT CTF) I killed the process. I brought forward a WU of 349 this way.
Now I run Boinc on a Quad core, running Vista, running internet, so hopefully what I explaned to you makes sense.

Kind regards,

Mark



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Message 720544 - Posted: 1 Mar 2008, 23:58:18 UTC - in response to Message 719730.

2. Is there any function of "Optimal function choice" group that uses (tries) 3DNow! ?

(As you know the older AMD processors - K6-2 ... early Athlons/Durons - do not have SSE)
(On K6-2+ everytime FPU is choosen)


No. There is not enough programmers on BOINC that know enough about 3DNow! to make optimizations for it. Someone was going to try to modify the open source SETI program to add it, but as far as I know they haven't done so in over a year.
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Message 721785 - Posted: 4 Mar 2008, 3:46:03 UTC - in response to Message 720533.


I think it depends on what setting you have configured Boinc, is your setup always on WU load en 100%, than your CPU will divide the task in 2, your game and Boinc. If you got 2 CPU's than you 'll never have a problem. I did have, still do, a K6 AMD and when I played games local, SETI will be online on the background, never had a problem, only when I went online (game of UT CTF) I killed the process. I brought forward a WU of 349 this way.
Now I run Boinc on a Quad core, running Vista, running internet, so hopefully what I explaned to you makes sense.

Kind regards,

Mark



(My setting is 100% CPU all the time)

My question is not about will BOINC/SETI work in the background -
it works if there are free CPU cycles.

It will not "divide the task in 2, your game and Boinc" (if you mean 50%/50%).
SETI task runs at Low/Idle priority (as you can see by Task Manager)
and it only gets CPU time when no other process needs CPU time.

(if the game needs 30% CPU and other processes use 10% than SETI will get 60%)
(if the game uses about 90% CPU and other processes use about 10% than SETI will get no more than 1-3% of CPU time)

This doesn't depend on how many cores your CPU has except the fact
that this kind of CPU has more computing power and it is hard to heavy load all of them.

I think that BOINC starts one SETI task per core
(on Quad Core CPU there are 4 SETI tasks running simultaneously - each on its own core).
If the game is not designed for multiprocessor/multicore system it will load just 1 core.

BOINC application itself runs at normal priority but uses very little CPU time.


So...
My question is about a thing which occurs when SETI task is Started or Restarted.
(Manually or (most of the time) - automaticly)

At this moment "Optimal function choice" is made (by setiathome_enhanced 5.27).
(On fast (2-3 GHz) CPU it lasts 5-10 seconds, on slow (500 MHz) - 1-3 minutes.)

Multiple functions are "tried" to measure which one is the best (fastest) for given CPU/computer.

These functions are written to do the same computation by using different
instruction sets (FPU, SSE, SSE2, SSE3, SSE4?...) supported by the CPU.


Despite the fact that it is a short process it has impact on the computing speed of entire WorkUnit
which varies in my case from 4 hours (Athlon 64 3500+ using SSE) to 4 days (K6-2+ 500 MHz using FPU).


So I wonder what will happen (what function will be choosen) if some functions are "tried" when computer
is Idle "loaded" (e.g. you are reading something on the screen (maybe this post :) ))
and the next moment (while other functions are "tried") you start something "heavy"
(e.g. 3D game, DivX coding, RAR compressing, CPU Burn-In utility,...) (and stop it after a few minutes).

Will this affect the next hours or days of SETI computing speed?


So I don't know what happens if:
"
1. During "Optimal function choice" by setiathome_enhanced 5.27
if I start some heavy task (e.g. game) in the middle of this process will this affect it?

(the functions executed when "heavy task" is running will take longer -
will this fool the setiathome_enhanced 5.27 that they are not optimal)
"
.


Profile BilBg
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Message 726286 - Posted: 14 Mar 2008, 23:49:57 UTC
Last modified: 15 Mar 2008, 0:00:49 UTC

.

Can somebody give me a link to the source files of "setiathome_enhanced 5.27"
so I can try to find the answer myself?

.

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Message 726297 - Posted: 14 Mar 2008, 23:59:33 UTC - in response to Message 726286.

http://setiathome.berkeley.edu/sah_porting.php
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Jord

Fighting for the correct use of the apostrophe, together with Weird Al Yankovic

Questions and Answers : Wish list : Optimal function choice

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