Low-cost number-cruncher

[DanceswithUnix]

I'm looking to build a cheap but quick linux PC. This will be used for running my own command-line based software. No desire for high-end sound or graphics, just plenty of grunt for wading through lots of floating point calculations.

I've decided on Intel, as AMD seems to be at least double the price for the performance level I'm looking at. I was initially opting for a low end Pentium D (930) with a Core 2 Duo capable motherboard to give the option of an upgrade later. However, the Allendale E6300 is only around £10 more expensive and seems to be comparable in performance to a low-end AMD FX-60.

When you say you are doing floating point, is that using SSE instructions? I ask as the P4 seems built for SSE, but I find that on engineering style floating point calculations the AMD processors run rings around it.

Of course it could be that your number crunching runs only last a few seconds or minutes, in which case you won't care. Mine run half a day, so halving the performance would not be acceptable! I nearly bought a P4 until I managed to run some benchmarks.

[alsenior]

Crikey. That's pretty useful. Couple of questions. Has openmosix found its way into standard linux distros yet? (I was intending to use Suse 10.1 but am easily persuaded). Also, how do you think it would cope with a cluster of multi-core systems? You need to code multi-threaded to get the best out of the multi-core environment, but wouldn't this prevent openmosix from propogating the work around the rest of the cluster?

to a standard multithreded app it show the system to be one large system with all of those processors but the threads cant share memory(there has been work on this but it is still a work in progress and not near completion.) genrally app need to be cluster aware to be able to use the cluster most effectivle. as forf your question about suse, you need to download the kernal rpm for your kernal version already installed i would most recommend suse 9 as it uses the 2.4 series kernal because 2.6 openmosix is still in beta aqnd needs alot doing to it. to get the fastest possable cluster you could use slackware 10.1 as that still uses 2.4 series kernals and is quite easy to set up if you have a bit of practical linux experience(you need to know how to complie a kernal) but other than that it is supposed to be quire easy.

[DerbyJon]

When you say you are doing floating point, is that using SSE instructions? I ask as the P4 seems built for SSE, but I find that on engineering style floating point calculations the AMD processors run rings around it.

Of course it could be that your number crunching runs only last a few seconds or minutes, in which case you won't care. Mine run half a day, so halving the performance would not be acceptable! I nearly bought a P4 until I managed to run some benchmarks.

Eek. Dunno to be honest! My code is a mixture of multi-parameter analysis of historical data to look for patterns and natural physical modelling and ray-trace rendering of the resultant data. All written in C and compiled using gcc.

[DerbyJon]

to a standard multithreded app it show the system to be one large system with all of those processors but the threads cant share memory(there has been work on this but it is still a work in progress and not near completion.) genrally app need to be cluster aware to be able to use the cluster most effectivle. as forf your question about suse, you need to download the kernal rpm for your kernal version already installed i would most recommend suse 9 as it uses the 2.4 series kernal because 2.6 openmosix is still in beta aqnd needs alot doing to it. to get the fastest possable cluster you could use slackware 10.1 as that still uses 2.4 series kernals and is quite easy to set up if you have a bit of practical linux experience(you need to know how to complie a kernal) but other than that it is supposed to be quire easy.

To be honest I think this is beyond my powers at present! I've been developing on unix and linux on and off since 1988 but not from a sysadmin perspective. This will be the first linux system I've owned and certainly the first I've built. Keep us updated on the openMosix stuff though as I wouldn't mind giving it a try further down the line.