Win64 multi core not always used ?

Questions and answers about problems with the software, modules or functionality.
Post Reply
CCD1024
Posts: 5
Joined: Sun Aug 25, 2013 8:21 pm

Win64 multi core not always used ?

Post by CCD1024 »

Dear Ivo
I use Startools 64 on a brand new computer under win8 64 and core i7 3970X (6 cores / 12 threads)
As I compute 4096x4096 images with star repair process, I saw the WARP function only use 1 processor core when MODIFYING STAR (long) and the 12 threads when HEALING process.
So, this very slow down the process !

Is it normal ?

Best
Philippe
User avatar
admin
Site Admin
Posts: 2296
Joined: Thu Dec 02, 2010 10:51 pm
Location: Melbourne
Contact:

Re: Win64 multi core not always used ?

Post by admin »

Hi Philippe,

This is indeed expected behaviour. The effectiveness of making an algorithm multi-threaded, greatly depends on the nature of the algorithm. Algorithms that perform a lot of calculations but access little data are most effectively distributed across multiple threads, whereas algorithms that require a lot of memory access (the warp algorithm is such an algorithm) are much less effective when multi-threaded (they can even be slower!). The reason for the latter is that such memory-heavy threads are all constantly waiting for the memory bus in that case.
That said, I'm constantly looking for optimizations and it's probably a good idea to do some tests to see if we can optimize the warp algorithm some more. Multi-threading may yet play a role in this! :thumbsup:
Ivo Jager
StarTools creator and astronomy enthusiast
CCD1024
Posts: 5
Joined: Sun Aug 25, 2013 8:21 pm

Re: Win64 multi core not always used ?

Post by CCD1024 »

Hi Ivo
Thanks... I understand :doh:

:obscene-drinkingcheers:
Post Reply