http://mw.hh.se/wg211/index.php?action=history&feed=atom&title=WG211%2FM23Kiselyov 2026-04-05T20:58:41Z Revision history for this page on the wiki MediaWiki 1.43.5 http://mw.hh.se/wg211/index.php?title=WG211/M23Kiselyov&diff=2548&oldid=prev 2024-03-11T06:44:01Z

<p>Add Oleg&#039;s talk details</p> <p><b>New page</b></p><div>== The Mysteries of AXPY (Oleg Kiselyov) ==<br /> <br /> <br /> AXPY is one of the Basic Linear Algebra (BLAS) vector operations: vector addition aX+Y. It is a perfect target for classical optimizations like partial loop unrolling and scalar promotion. (AXPY is also embarrassingly parallel; however, this talk focuses on single-thread performance.) These optimizations are indeed carried out -- by hand -- in OpenBLAS, regarded as one of the two fastest BLAS implementations. One can make a case for automatic code generation, to reduce the tedium of applying such optimizations (given that there are many platforms and several AXPY varieties to optimize: SAXPY, DAXPY, CAXPY). This is the traditional elevator talk about metaprogramming in HPC.<br /> <br /> How does it correspond to real life, in this day and age?</div>

Jeremy-y