Yesterday I installed BOINC on a PC with a hyperthreading enabled CPU. I attached both setiathome and climateprediction, both had a resource share of 50%. BOINC has set one virtual CPU to seti and the other to cpdn. The seti wu took much much longer (about 3x) compared to when I had hyperthreading disabled. I assume that this is because both virtual CPUs are sharing CPU cache and RAM; and with different projects running the two virtual CPUs are requesting completely different data from the same cache.

Then I switched seti to 99,99%, and now on both virtual CPUs are seti work units done. The time for a _single_ work unit is much lower than it was first.

Maybe it would be better if BOINC would run only work units of the same project on two virtual CPUs, then switch to _two_ work units from the other project. Of course, BOINC would have to request at least one work unit per virtual CPU from every project.

so long,

Alex

Hi Alex

the last client I assembled was a HT based cpu,
exactly for running muliple project.

My settings are 87,5% seti and 12,5% cpdn

In one time the client takes 3 WUs (2 seti 1 cpdn)

the total cpu time for the seti WUs has not changed (in my environment)
with or without cpdn attached.

Now I using the boinc client 4.08 (too my own risk) and I'm extremly
satisfied with.

The multiproject client is running now 5 day, I have seen many changes of status (paused, running)
no one restart or abend sinse there run 24h/day

This client is going very smouth with seti (AND cpdn, 89h are done, left 521h.)

the settings are very individuell.

A bad question: do you see 2 virtual cpus on the taskmanager? and are they both using about 50% of cpu time?

with 50/50 you should see more "changes" and other times.

perhaps it's to early for you to see a progress.

Sometimes there is a need to spend more time and finetune settings until they looks fine for you.

so long
Goodluck!

Ric

BTW both projects returned credit

edit :
trying to put hardcopy
yes the ESTIMATED total time is higher, with this you are right

Hi,

> A bad question: do you see 2 virtual cpus on the taskmanager? and are they
> both using about 50% of cpu time?

On this system (P4 2,6GHz / XP SP2) I see two CPUs in the taskmanager and both are reporting exactly 100%. This seems new to SP2 or maybe to the chipset drivers, I expected to see about 55 % per CPU.

> This client is going very smouth with seti (AND cpdn, 89h are done, left
> 521h.)

Nothing to complain, progres and credits are fine... I just noticed that when two seti tasks are running one single wu takes about 4:30 to finish. Not the estimated time, the time reported after finishing. And when one seti task and one cpdn task is running at the same time, one single seti wu takes around 10 hours.

And I was wondering if it wouldn't be better to let run two tasks from project a, then two tasks from project b - according to the resource sharing - than to let run one task from the one and one from the other, you see?

I will do some checks tomorrow to get exact time data.

Alex

I would expect it to normally be better to have 2 different projects running at the same time on HT machines. To me that would seem to reduce the odds that both logical processors would want the same part of the physical processor at the same time. That doesn't mean that it would always be better though. For example a project may have a large enough working set to knock everything else out of the cache when it needs to execute. In that case it would cause everything on the computer to run slower because the cache would have to be reloaded every time a different process is executed.

John Keck -- BOINCing since 2002/12/08 --

I have 3 P4 HT Computers and their set up to run 50/50 between CPDN & SETI. From what I've noticed by watching how they do the different projects is that there is no set way they will do it...IMO

They may run 2 WU's from 1 Project for awhile & then 2 from the other Project for awhile. Then they may run 1 WU from each Project for awhile.