> Fra: Mark Rotteveel [mailto:m...@lawinegevaar.nl] > Emne: Re: [Firebird-devel] True SMP support in SuperClassic and V3 > > On Tue, 13 Nov 2012 14:18:22 +0000, Poul Dige <p...@tabulex.dk> wrote: > > I could put a screen dump here of the Windows 2008R2/63 task manager > with > > AMD Opteron 6274, 2x16 core running FB2.5.1 SC/32 bit (due to some 32 > bit > > UDF). I don't know if you are interested at a gaze. We see exactly the > same > > kind of usage, 8 cores are in use and 24 are more or less doing nothing. > > > > > However, the cores in use are not maxed out - so it COULD be something > > with power management that the OS doesn't want to activate more CPU's > than > > necessary. I can't tell about that for sure. > > I know that Windows 8 will 'park' cores if there is no work for them, and it > will > try to assign threads to the active/unparked cores first. When the load > exceeds a certain threshold, then it will unpark an additional core and > schedule threads to that (at least that is what I observed on my Windows 8 > Pro on an 8 'core'(*) FX-8120 at home), as far as I know Windows > 2008 server also has similar scheduling algorithms (depending on the > processor). > > The reason is simple: it conserves some power, and some processor have a > kind of speed boost when not all cores are loaded (ie: it will 'overclock' > the active cores because there is more thermal 'headroom' as not all cores > are powered and generating heat). This allows for faster processing if work > isn't really multithreaded, and doesn't actually benefit much from running > multicore. > > (*): Actually the AMD FX is not fully 8 core, it is more like a 4 core which > allows 2 threads to be scheduled simultaneously by having same > features/instructions twice, and other features/instructions only once per > core. > > Mark
Maybe this article about core parking will be of interest - amazing, what you can Google nowadays: http://support.microsoft.com/kb/2646060 Regards, Poul ------------------------------------------------------------------------------ Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
