[Beowulf] Peformance penalty when using 128-bit reals on AMD64
Many of your questions may have already been answered in earlier discussions or in the FAQ. The search results page will indicate current discussions as well as past list serves, articles, and papers.
Prentice Bisbal prentice at ias.eduFri Jun 25 07:28:15 PDT 2010
- Previous message: [Beowulf] [hpc-announce] Deadline extended: CFP: Workshop on Interfaces and Abstractions for Scientific Data Storage (IASDS 2010)
- Next message: [Beowulf] Peformance penalty when using 128-bit reals on AMD64
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Beowulfers, One of my Fortran programmers had to increase the precision of his program so he switched from REAL*8 to REAL*16 which changes the size of his variables from 64 bits to 128 bits. The program now takes 32x longer to run. I'm not an expert on processor archtitecture, etc., but I do know that once the size of a variable exceeds the size of the processors registers, things will slow down considerably. Is his 32x performance degradation in line with this? Is there any way to reduce this degradation? Would The GNU GMP library (or some other library) help speed things up? -- Prentice
- Previous message: [Beowulf] [hpc-announce] Deadline extended: CFP: Workshop on Interfaces and Abstractions for Scientific Data Storage (IASDS 2010)
- Next message: [Beowulf] Peformance penalty when using 128-bit reals on AMD64
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
More information about the Beowulf mailing list