dear R experts: although my question may be better asked on the HPC R mailing list, it is really about something that average R users who don't plan to write clever HPC-optimized code would care about: is there a quantum performance leap on the horizon with CPUs?
like most R average non-HPC users, I want to stick mostly to mainstream R, often with library parallel but that's it. I like R to be fast and effortless. I don't want to have to rewrite my code greatly to take advantage of my CPU. the CUDA forth-and-back on the memory which requires code rewrites makes CUDA not too useful for me. in fact, I don't even like setting up computer clusters. I run code only on my single personal machine. now, I am looking at the two upcoming processors---intel haswell (next month) and amd kaveri (end of year). does either of them have the potential to be a quantum leap for R without complex code rewrites? I presume that any quantum leaps would have to come from R using a different numerical vector "engine". (I tried different compiler optimizations when compiling R (such as AVX) on the 1-year old i7-27*, but it did not really make a difference in basic R benchmarks, such as simple OLS calculations. I thought AVX would provide a faster vector engine, but something didn't really compute here. pun intended.) I would guess that haswell will be a nice small evolutionary step forward. 5-20%, perhaps. but nothing like a factor 2. [tomshardware details how intel FP32 math is 4 times as fast as double math on the i7 architecture. for most of my applications, a 4 times speedup at a sacrifice in precision would be worth it. R seems to use only doubles---even as.single is not even converting to single, much less inducing calculations to be single-precision. so I guess this is a no-go. correct?? ] kaveri's hUMA on the other hand could be a quantum leap. kaveri could have the GPU transparently offer common standard built-in vector operations that we use in R, i.e., improve the speed of many programs without the need for a rewrite, by a factor of 5? hard to believe, but it would seem that AMD actually beat Intel for R users. a big turnaround, given their recent deemphasis of FP on the CPU. (interestingly, the amd-built Xbox One and PS4 processors were also reported to have hUMA.) worth waiting for kaveri? anything I can do to drastically speed up R on intel i7 by going to FP32? regards, /iaw ---- Ivo Welch (ivo.we...@gmail.com) ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.