4 ms·
Does anyone know if the current/recent processors from Intel and AMD still perform relatively slowly in number crunching with denormals and NaNs? I remember it
by Serow225 12y ago
Does anyone know if the current/recent processors from Intel and AMD still perform relatively slowly in number crunching with denormals and NaNs? I remember it used to be like hitting a brick wall performance-wise if these crept into your data...
- acqq 12y agoAMD since long a while wasn't as slow for NANs whereas a few generations ago Intel was certainly 100 times slower as soon as the NANs are there. The first processors that aren't are Sandy Bridge ones, apparently.
- stephencanon 12y agoInf and NaN have been handled at speed at least as far back as Core (probably on P4 too, but I'm not certain, as I never really worked with those). [edit: I’m referring to SSE/AVX; I forget that there are people who still use x87, where this stall is still around]. Denormal stalls, which are on the order of 100x, started to go away for addition in SNB. (IIRC, AMD doesn't handle denormals at speed either, but I'd need to double-check that).
- Serow225 12y agoThanks, yes I was thinking of both x87 and not just vector instructions. Any other info you have would be helpful :)