System suggestion - Page 3

Admiral Huddy · 12-02-2008, 15:36

Quote:

Originally Posted by Daz

I dont get this trend people seem to having of setting affinity for processes, especially now HT isnt in the chips. The scheduler does a perfectly good job of managing threads for you, seems daft to interfere :S

I've seen a massive improvement to performance when video editing and encoding at the same time if I set the afinity of the encoding to use dedecitated cores seperate from the ones I'm using. This means there is no impact on what I'm doing. It's like a batch run. On the other hand, not settting the afinity takes a chunk of my interactive processing. I've found unless 'm doing something wrong!

I'm sure I read somewhere that HT is returning, giving a futher 4 logical cores on top of the 4 physical

Daz · 12-02-2008, 15:49

'The ones I'm using'... you're, or rather the system is using all of them

The scheduler is aware of a lot more in the system than you or I, it's better placed to make decisions about process/thread affinity and has done that job well (both Linux and Windows kernels) for many years. If you're really seeing a benefit forcing process affinity then I'd suggest it's bad programming somewhere. Lord knows I've never gone around tailoring affinity on SQL/Exchange/Oracle/<generic transactional database engine> before, or ever felt the need to.

HT's return is certain I think, though second time round should be better. The kernel/scheduler and hopefully in turn the applications will be better aware of the HT cores, so hopefully they'll be used more appropriately.

Every server here that has an HT CPU has it disabled in the BIOS - the performance hit you take doing some things is much worse than the odd benefit, so it was killed as a matter of policy here.

Mark · 12-02-2008, 19:21

@Daz. No, it seems the scheduler (at least the one in XP) doesn't do a good enough job on its own.

Painkiller, for example, goes nuts. Jumpy graphics, broken sound etc. Set affinity to one core and it all goes away.

Now, this probably isn't the scheduler's fault. Rather it's old software not expecting multiple cores. Either way, it shows that sometimes the scheduler needs help.

Stan_Lite · 12-02-2008, 20:07

Many of us in team 10, running the WinSMP client, are using an application called the Fah SMP Affinity Changer which runs as a service and automatically alters affinities to optimise core usage by the SMP client. Most of us are seeing 15-20% gains in output using it. If the scheduler was up to the task, this wouldn't be required.
Windows will probably do a half decent job for most everyday applications but sometimes it needs a helping hand.

MarcLister · 13-02-2008, 12:52

Quote:

Originally Posted by Admiral Huddy

Having owned a quad core since November, I don't see any advantage to that of a dual core. At this time. If I have to run multiple tasks, then I have to set affinity to ensure that two apps, for example, are grabbing equal processing power. IMO, the E8400 is bargain and 4GHz is easy achievable. This would be my CPU of choice for the time being unless there are some radical changes in mutli-threaded applications. However, server apps may benefit.

But your e-peen score > *.

leowyatt · 13-02-2008, 13:01

Erm does the above discussion have any impact on the system suggestions

Stan_Lite · 13-02-2008, 13:28

Ah, sorry. I didn't realise I was in the only thread in BD that's not allowed to go off topic

I think you'd be hard pushed to better that Dell system that Rich_L posted for value for money. There's no way I could build that system for anywhere near that price and you also get their "Next business day" warranty.

As Rich suggests, spec it up a bit with more RAM and another HDD (iirc, Dell will do the RAID for you as well, if you want it) and you've got a cracking system that will do everything your mate needs and more. The graphics card in that system will easily run dual monitors and the Q6600 is a very good CPU - quad core may be overkill but at that price ...............

I'd go for it.

Admiral Huddy · 13-02-2008, 13:31

..but this is the Computer forum so we can

We are trying to decide if the potential RAW power of a dual core (E8400) > benefit of a quad core processor. In terms of pricing, there's little in it but it all depends on the usage of the PC. The way I see it, the quad core takes a little tweaking around to get the most from it.

Don'r forget to check Novatech too

They normally have decent spec machines at good prices.

Daz · 13-02-2008, 13:33

Quote:

Originally Posted by Bigstan

(iirc, Dell will do the RAID for you as well, if you want it)

They certainly do on the business systems (Optiplex/Precision/Vostro), and I dont see why they wouldn't on the desktop models. Limited to 1 and 0 but that's all you'll need

Feek · 13-02-2008, 14:29

Quote:

Originally Posted by Kitten

As I said...relate it to the OP and all's good

Otherwise I'll be getting my cane out.

/me goes wildly off topic and bends over....

12-02-2008, 15:49	#22
Daz The Stig Join Date: Jun 2006 Location: Swad! Posts: 10,713	'The ones I'm using'... you're, or rather the system is using all of them The scheduler is aware of a lot more in the system than you or I, it's better placed to make decisions about process/thread affinity and has done that job well (both Linux and Windows kernels) for many years. If you're really seeing a benefit forcing process affinity then I'd suggest it's bad programming somewhere. Lord knows I've never gone around tailoring affinity on SQL/Exchange/Oracle/<generic transactional database engine> before, or ever felt the need to. HT's return is certain I think, though second time round should be better. The kernel/scheduler and hopefully in turn the applications will be better aware of the HT cores, so hopefully they'll be used more appropriately. Every server here that has an HT CPU has it disabled in the BIOS - the performance hit you take doing some things is much worse than the odd benefit, so it was killed as a matter of policy here. __________________ apt-get moo

12-02-2008, 20:07	#24
Stan_Lite Stan, Stan the FLASHER MAN! Join Date: Jul 2006 Location: In bed with your sister Posts: 5,483	Many of us in team 10, running the WinSMP client, are using an application called the Fah SMP Affinity Changer which runs as a service and automatically alters affinities to optimise core usage by the SMP client. Most of us are seeing 15-20% gains in output using it. If the scheduler was up to the task, this wouldn't be required. Windows will probably do a half decent job for most everyday applications but sometimes it needs a helping hand. __________________ Just because I have a short attention span doesn't mean I...

13-02-2008, 13:01	#26
leowyatt Chef extraordinaire Join Date: Jul 2006 Location: Infinite Loop Posts: 11,143	Erm does the above discussion have any impact on the system suggestions __________________ "Dr Sheldon Cooper FTW!"

13-02-2008, 13:28	#27
Stan_Lite Stan, Stan the FLASHER MAN! Join Date: Jul 2006 Location: In bed with your sister Posts: 5,483	Ah, sorry. I didn't realise I was in the only thread in BD that's not allowed to go off topic I think you'd be hard pushed to better that Dell system that Rich_L posted for value for money. There's no way I could build that system for anywhere near that price and you also get their "Next business day" warranty. As Rich suggests, spec it up a bit with more RAM and another HDD (iirc, Dell will do the RAID for you as well, if you want it) and you've got a cracking system that will do everything your mate needs and more. The graphics card in that system will easily run dual monitors and the Q6600 is a very good CPU - quad core may be overkill but at that price ............... I'd go for it. __________________ Just because I have a short attention span doesn't mean I...

13-02-2008, 13:31	#28
Admiral Huddy HOMO-Sapien Join Date: Jun 2006 Location: Chelmsford Posts: 6,692	..but this is the Computer forum so we can We are trying to decide if the potential RAW power of a dual core (E8400) > benefit of a quad core processor. In terms of pricing, there's little in it but it all depends on the usage of the PC. The way I see it, the quad core takes a little tweaking around to get the most from it. Don'r forget to check Novatech too They normally have decent spec machines at good prices. __________________ I just got lost in thought.. It was very unfamiliar territory. Techie Talk \| My gaming Blog \| PC spec \| The Admirals log Last edited by Admiral Huddy; 13-02-2008 at 13:34.

12-02-2008, 19:21	#23
Mark Screaming Orgasm Join Date: Jul 2006 Location: Newbury Posts: 15,194	@Daz. No, it seems the scheduler (at least the one in XP) doesn't do a good enough job on its own. Painkiller, for example, goes nuts. Jumpy graphics, broken sound etc. Set affinity to one core and it all goes away. Now, this probably isn't the scheduler's fault. Rather it's old software not expecting multiple cores. Either way, it shows that sometimes the scheduler needs help.