Quads & Seti

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Message 619544 - Posted: 15 Aug 2007, 13:18:26 UTC

Hi Everyone.

I have a question which is in 2 parts.

1: I want to build a home server using a quad core - is it posssible to use each core for a seperate function, i.e., Web,E-Mail,File & Intranet servers?

2: If yes, can s@h run with all 4 cores without infringing on the server aspects?
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Message 619552 - Posted: 15 Aug 2007, 13:40:03 UTC

Well that sort of happens automatically. Most programs out there today are not designed to work on multi cores, including Seti and Boinc. The CPU instruction set will allocate processing requests to any available core. If you are thinking that all emails goes thur core 0 then all file processing thur core 1 and all music thur core 3, etc. No that is not possible. What will happen is that if an email process request hits the cpu and core 0 is available, then core 0 will perform the operation. If core 3 is available then core 3 will perform it. All while Seti crunchs away.
Hope this simple answer helps.
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Message 619565 - Posted: 15 Aug 2007, 14:27:16 UTC - in response to Message 619552.  

Well that sort of happens automatically. Most programs out there today are not designed to work on multi cores, including Seti and Boinc. The CPU instruction set will allocate processing requests to any available core. If you are thinking that all emails goes thur core 0 then all file processing thur core 1 and all music thur core 3, etc. No that is not possible. What will happen is that if an email process request hits the cpu and core 0 is available, then core 0 will perform the operation. If core 3 is available then core 3 will perform it. All while Seti crunchs away.
Hope this simple answer helps.


Thanks Carlos, that's good enough for me. I just needed to know that there would be no holdups. From your explanation, it seems that a quad core with 4gb ram will be sufficient for my needs.

do you think 4gb is enough?
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Message 619570 - Posted: 15 Aug 2007, 14:41:57 UTC

You can, however, force a particular process or program to use only one particular core. The processor affinity setting should allow you to do this under windows on all but core parts of the OS.
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Message 619609 - Posted: 15 Aug 2007, 15:42:43 UTC - in response to Message 619565.  

do you think 4gb is enough?

I think you'll find 4Gigabytes to be plenty, unless you run some RAM-hogging application you have not mentioned.

You can set processor-affinity for the currently executing instance of any process in Windows Task Manager. However you are very unlikely to find benefit in doing so, and the affinity will be forgotten when that instance terminates.

I'm typing to you on a recently built Q6600 quad running SETI and Einstein with 4Gbytes of RAM. Since I run Windows XP, about a half Gig of the RAM is not usable. The system runs just dandy. Don't judge the SETI suitability from my low RAC--I'm only allocating 8% to SETI, and the system is too new for the RAC to have stabilized.

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Message 619613 - Posted: 15 Aug 2007, 15:56:50 UTC - in response to Message 619609.  

setting up affinity is never a very good idea. you 'll figure out quickly if you try.

Let the kernel of your OS deal with it.
If you set up affinities, for example, Outlook will become a serial program, and will give you the appearance of hanging some time, while it just spawned 2 threads, one for interface, one for reading from the server.

except for application that you know perfectly the behavior, with no IO, you can play with this.
Remember as well that IO is very often sent to a separated thread, to avoid user interface glitch. if you set up affinity, it is re-enforced that the child thread will sit on the same CPU too. You 'll lose the benetif of having a Quad core, in a responce time related test.

in the case of seti, on a Quad core, I run 100% SETI or rosetta, and I usually don t feel it when i work. If i run something heavier, i use the task bar button "snozze" and that will free my CPUs.

just my 2 cents.

who?
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Message 619618 - Posted: 15 Aug 2007, 16:02:35 UTC - in response to Message 619613.  

setting up affinity is never a very good idea.
Agreed who?, on rereading my post I realize it is not so negative as my actual belief.

By the way, it would be good to upgrade your KWSN application from 2.2B to 2.4.

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Message 619621 - Posted: 15 Aug 2007, 16:07:23 UTC - in response to Message 619613.  

setting up affinity is never a very good idea. you 'll figure out quickly if you try.

Let the kernel of your OS deal with it.
If you set up affinities, for example, Outlook will become a serial program, and will give you the appearance of hanging some time, while it just spawned 2 threads, one for interface, one for reading from the server.

except for application that you know perfectly the behavior, with no IO, you can play with this.
Remember as well that IO is very often sent to a separated thread, to avoid user interface glitch. if you set up affinity, it is re-enforced that the child thread will sit on the same CPU too. You 'll lose the benetif of having a Quad core, in a responce time related test.

in the case of seti, on a Quad core, I run 100% SETI or rosetta, and I usually don t feel it when i work. If i run something heavier, i use the task bar button "snozze" and that will free my CPUs.

just my 2 cents.

who?


~ off topic ~
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~ on topic ~
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Message 619626 - Posted: 15 Aug 2007, 16:20:36 UTC - in response to Message 619618.  

setting up affinity is never a very good idea.
Agreed who?, on rereading my post I realize it is not so negative as my actual belief.

By the way, it would be good to upgrade your KWSN application from 2.2B to 2.4.

"Who?" might still be running His own app, Of course He may try and make His own 2.4 compatible version for all I know. Only "Who?" knows for sure. :D
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Message 619632 - Posted: 15 Aug 2007, 16:31:11 UTC - in response to Message 619544.  
Last modified: 15 Aug 2007, 16:31:41 UTC

Hi Everyone.

I have a question which is in 2 parts.

1: I want to build a home server using a quad core - is it posssible to use each core for a seperate function, i.e., Web,E-Mail,File & Intranet servers?

2: If yes, can s@h run with all 4 cores without infringing on the server aspects?

If this is in fact a home server, you might want to consider a much smaller processor.

None of the functions you mentioned in #1 are generally difficult. Basic web serving is opening a file and writing it out to the network. E-Mail is a little more involved if you're also fighting spam, but that's network-intensive (I/O intensive) and not CPU-intensive. Extra RAM is better than more CPU.

The disadvantage to running your own server is that it will always be on.

Setting aside SETI, a single VIA C3 running under 1 GHz would do these functions very nicely, and you could keep the power draw under 30 watts. It'd also be QUIET which is sometimes nice at home.

I know about servers and loads, I run an ISP.

-- Ned
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Message 619643 - Posted: 15 Aug 2007, 16:53:17 UTC - in response to Message 619632.  

If this is in fact a home server, you might want to consider a much smaller processor.
...
Setting aside SETI, a single VIA C3 running under 1 GHz would do these functions very nicely, and you could keep the power draw under 30 watts. It'd also be QUIET which is sometimes nice at home.
-- Ned

Agreed.

But if running SETI is of interest to you, then a Q6600 will give you more BOINC work per watt, or per dollar than most alternatives. If BOINC work/watt is of interest, then don't overclock past the point of requiring much voltage increase.

As to quiet, assuming you are not seeking silence, the big key is:
large-diameter fans turning slowly.

My Q6600 Quad system uses an Enzotech Ultra-X Heatsink/Fan with a 120mm integral fan turning about 1800 rpm, with a Seasonic power supply that also has a 120mm integral fan, in a case with a 120mm exhaust fan. Sadly the case only has provision for a pair of 92mm inlet fans. The air flow/noise tradeoff for these larger fans is vastly superior to the 80mm fans I used before.

Again, staying at modest or zero overclock will help you use quieter cooling if that is a consideration.

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Message 619907 - Posted: 15 Aug 2007, 23:09:51 UTC
Last modified: 15 Aug 2007, 23:12:42 UTC

do you think 4gb is enough?


No idea/experience with servers. Currently I don't have alternatives to a Laptop so that's what I use. When I had been in the shop recently to ask about a new Laptop with a C2D, I was told not to exceed 2gig of RAM, because it's a 32bit CPU, which can't use a bigger amount properly. It may be different with quads(which I don't think) or for servers, no idea.

Happy crunching, Christoph
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Message 619916 - Posted: 15 Aug 2007, 23:19:19 UTC - in response to Message 619907.  
Last modified: 15 Aug 2007, 23:19:49 UTC

do you think 4gb is enough?


No idea/experience with servers. Currently I don't have alternatives to a Laptop so that's what I use. When I had been in the shop recently to ask about a new Laptop with a C2D, I was told not to exceed 2gig of RAM, because it's a 32bit CPU, which can't use a bigger amount properly. It may be different with quads(which I don't think) or for servers, no idea.

Happy crunching, Christoph


Actually, with 32bit addressing, the limit is 4GB total. Due to the way 32bit hardware was designed, only 2GB can be accessed by a single application (though there's not too many home machines-based software that actually needs that much other than some newer games).

However, ever since the Pentium Pro (the first Intel 686-class chip), a special memory addressing mode is available up to 36bit, which allows for a total of 64GB of addressable memory. Unfortunately, this requires an OS that supports this 'feature' (Linux fans will quickly point out that Linux supports this feature, some version of Windows did until Microsoft artificially limited it to 32bit addressing with later "patches"), and it still does nothing for the application barrier of 2GB.
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Message 619917 - Posted: 15 Aug 2007, 23:19:45 UTC - in response to Message 619613.  

setting up affinity is never a very good idea. you 'll figure out quickly if you try.

Let the kernel of your OS deal with it.
If you set up affinities, for example, Outlook will become a serial program, and will give you the appearance of hanging some time, while it just spawned 2 threads, one for interface, one for reading from the server.

except for application that you know perfectly the behavior, with no IO, you can play with this.
Remember as well that IO is very often sent to a separated thread, to avoid user interface glitch. if you set up affinity, it is re-enforced that the child thread will sit on the same CPU too. You 'll lose the benetif of having a Quad core, in a responce time related test.

in the case of seti, on a Quad core, I run 100% SETI or rosetta, and I usually don t feel it when i work. If i run something heavier, i use the task bar button "snozze" and that will free my CPUs.

just my 2 cents.

who?



Would there be any advantages to running seti@home's science app with an affinity?
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Message 619922 - Posted: 15 Aug 2007, 23:26:18 UTC - in response to Message 619917.  


Would there be any advantages to running seti@home's science app with an affinity?

I have to stretch to find an advantage at all, here is my bid:

As the system is less able to keep the cores 100% loaded, you'd get slightly lower power consumption. But you would lower total useful throughput. This is generally a quite bad idea.


(and yes, as an experiment I tried setting individual affinities for the four current running BOINC science applications on my Q6600. I watched the utilization drop a bit from its normal steady 100%. So I'm not just saying this in principle.
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Message 619925 - Posted: 15 Aug 2007, 23:33:48 UTC - in response to Message 619643.  

If this is in fact a home server, you might want to consider a much smaller processor.
...
Setting aside SETI, a single VIA C3 running under 1 GHz would do these functions very nicely, and you could keep the power draw under 30 watts. It'd also be QUIET which is sometimes nice at home.
-- Ned

Agreed.

But if running SETI is of interest to you, then a Q6600 will give you more BOINC work per watt, or per dollar than most alternatives. If BOINC work/watt is of interest, then don't overclock past the point of requiring much voltage increase.

As to quiet, assuming you are not seeking silence, the big key is:
large-diameter fans turning slowly.

My Q6600 Quad system uses an Enzotech Ultra-X Heatsink/Fan with a 120mm integral fan turning about 1800 rpm, with a Seasonic power supply that also has a 120mm integral fan, in a case with a 120mm exhaust fan. Sadly the case only has provision for a pair of 92mm inlet fans. The air flow/noise tradeoff for these larger fans is vastly superior to the 80mm fans I used before.

Again, staying at modest or zero overclock will help you use quieter cooling if that is a consideration.

If the goal is "have a server at home" then the Q6600 is massive overkill.

If the goal is "get a really trick SETI cruncher, and use it in some other cool ways" then that is very different.

... and I'm certainly not arguing against the cruncher. If I'm buying a cruncher that'd be pretty high on my list.

I would not consider a Q6600 for an internet/intranet/file server. It's overkill.
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Message 619926 - Posted: 15 Aug 2007, 23:39:09 UTC

I have been running win xp pro with a AMD 4800+ dual core. I usually don't, but I have played with the affinities sometimes. Usually, on this machine the usage will stay at 100%. The behavior that I have seen is that one core will usually stay at 50% (in the task manager) and the other core will vary with what other programs are running.
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Message 619969 - Posted: 16 Aug 2007, 0:33:11 UTC - in response to Message 619926.  

i think a quad-core for a local server is overkill also, i use a Dual 433MHz celeron 1 board {Abit BP6} and crunch seti while it running 24/7 {been down for a recap}.
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Message 620012 - Posted: 16 Aug 2007, 2:11:42 UTC - in response to Message 619969.  

i think a quad-core for a local server is overkill also, i use a Dual 433MHz celeron 1 board {Abit BP6} and crunch seti while it running 24/7 {been down for a recap}.


Fantastic - thanks guys.

I have read all the posts on this & have even saved it offline for future reference.

Windows Home Server will be released shortly & it is looking good. I will be using that for what it is.

However, I also require a Web/E-Mail/Intranet Server for business use.

I am a local OEM system builder & registered as a Microsoft Partner.

I want the WHS software to operate on my home network & if possible use the same software to operate the business side.

I don't want the business side to catch sight of the home sight & vice versa without have to build seperate servers.

So will a quad manage all this or will a dual core suffice?
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Message 620028 - Posted: 16 Aug 2007, 2:46:33 UTC - in response to Message 620012.  

i think a quad-core for a local server is overkill also, i use a Dual 433MHz celeron 1 board {Abit BP6} and crunch seti while it running 24/7 {been down for a recap}.


Fantastic - thanks guys.

I have read all the posts on this & have even saved it offline for future reference.

Windows Home Server will be released shortly & it is looking good. I will be using that for what it is.

However, I also require a Web/E-Mail/Intranet Server for business use.

I am a local OEM system builder & registered as a Microsoft Partner.

I want the WHS software to operate on my home network & if possible use the same software to operate the business side.

I don't want the business side to catch sight of the home sight & vice versa without have to build seperate servers.

So will a quad manage all this or will a dual core suffice?

As a rule of thumb, servers don't need fast processors. They need lots of memory and fast disks.

A dual-core processor is probably overkill for home, and certainly more than adequate for the office, even running resource hogs like Exchange.

... unless you're also crunching SETI.

If you also want to play with different configurations, I'd think about something that'd run VMware Server well.
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