On Wednesday 04 March 2009 16:29:30 Bill Hart wrote: > My guess would be stalls due to unavailability of data from the cache > in time for the pipeline. Some insertions of nop's would probably make > this go away. That may or may not affect the timings on Opteron. > > I suspect it is only an issue on cheaper processors like the Athlon 64 > x2 and Turion 64 x2. I have one of the latter, and it would be > interesting to try out. I have linux on this machine so I could > possibly give it a go. But it might be tomorrow before I get to it. > > I also have an Athlon 64 x2 at home. > > It's not clear how much effort we should expend on optimisation for > home market PC's. I'm not saying we shouldn't do it. I'm just saying > it is not clear how much we should do for it. > > Bill.
My K8(sempron) cost less than two pizza's , and it runs addmul just great. K8 £15 m/b £23 mem £8 rest of the system is crap > > 2009/3/4 <ja...@njkfrudils.plus.com>: > > - Show quoted text - > > > > On Wednesday 04 March 2009 15:57:25 Cactus wrote: > >> On Mar 4, 3:49 pm, ja...@njkfrudils.plus.com wrote: > >> > On Wednesday 04 March 2009 15:40:04 Bill Hart wrote: > >> > > This is on a K10. The runs differ significantly. Interesting. > >> > > > >> > > It might have to do with the almost completely unpredictable > >> > > scheduling on the K10. Certainly the differences at limb n are > >> > > almost always made up again, or nearly so, at limb n+1, and by the > >> > > end of 40 limbs the times are usually within a cycle or so. On > >> > > average performance doesn't vary. > >> > > > >> > > Bill. > >> > > >> > My K8 is very stable, the K10(cuda1) a bit less so , and I found the > >> > core2 (sage.math) to be all over the place . You could try increasing > >> > the precision , yet again. > >> > > >> > > 2009/3/4 Jeff Gilchrist <jeff.gilchr...@gmail.com>: > >> > > > On Wed, Mar 4, 2009 at 10:27 AM, Bill Hart > >> > > > <goodwillh...@googlemail.com> > >> > > >> > wrote: > >> > > >> I've just noticed that the times from speed are not consistent > >> > > >> between runs!! I thought that was almost impossible. > >> > > > > >> > > > I did several runs on my systems and they all agreed for me, even > >> > > > when the system was loaded or not. > >> > > > > >> > > > Jeff. > >> > > > - Show quoted text - > >> > >> I do see some variation on my Core 2 portable but my Athlon X2 gives > >> consistent results. The variation on the Core 2 is not large enough to > >> worry about. > >> > >> By the way, does anyone have a theory about the mpn_mul_1 curve (2nd > >> to bottom) that goes up and down regularly? > > > > thats the green line , your windows K8 > > > > mpn_mul_1 and mpn_addmul_1 on K8 are the same function(practically) , but > > the addmul doesn't display that behavour. > > - Show quoted text - > > > >> Brian > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "mpir-devel" group. To post to this group, send email to mpir-devel@googlegroups.com To unsubscribe from this group, send email to mpir-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/mpir-devel?hl=en -~----------~----~----~----~------~----~------~--~---
