What is a flop?
nhigham.com
What is a flop?
1–10 of 41 posts
Re: What is a flop?
#2I'm usually a fan of Higham, but the last few posts have been weak.
Re: What is a flop?
#3I'm usually a fan of Higham, but the last few posts have been weak.
Flops ?
Re: What is a flop?
#4[deleted]
Re: What is a flop?
#5Floating point operations per …?
Re: What is a flop?
#6Floating point operations per …?
Floating Point Operations Per Second [1]
Re: What is a flop?
#7My personal notes on this subject:
* MIPS was perhaps the integer equivalent to FLOP, still used in modern microcontrollers because the 8051 at 12MHZ would only execute 1MIPS (12 clocks per instruction). Modern 8051 chips obviously have sped up to 1 clock per instruction, but MIPS (and Dhrystone MIPS in particular) are still a common benchmark today.
* FLOPs is very difficult to calculate in theory because modern CPUs have vector units, and multiple pipelines per core. You could have 3x AVX512 instructions in parallel on today's CPUs on a single core.
* FLOPs we're traditionally a 64-bit operation for the supercomputer community. Today, most FLOPs are 32-bit for video games. Finally, the deep learning / neural net guys have popularized 16-bit flops, and even 8-bit iops.
* 'The' flop is a misnomer because it's almost always the multiply-and-accumulate instruction: X = A + B * C. Which... Is two operations per instruction (per shader/SIMD lane). Eeehhh whatever. Who cares about these details?
* As 'Dhrystone' is the benchmark for MIPS, the benchmark for 64-bit flops is Linpack.
Re: What is a flop?
#8Floating point operations per …?
Floating Point Operations Per Second [1] [1] https://academickids.com/encyclopedia/index.php/FLOPS
> One should speak in the singular of a FLOPS and not of a FLOP, although the latter is frequently encountered. The final S stands for second and does not indicate a plural.
The author of this post seems to have fallen for this error.
Re: What is a flop?
#9Re: What is a flop?
#10My personal notes on this subject: * MIPS was perhaps the integer equivalent to FLOP, still used in modern microcontrollers because the 8051 at 12MHZ would only execute 1MIPS (12 clocks per instruction). Modern 8051 chips obviously have sped up to 1 clock per instruction, but MIPS (and Dhrystone MIPS in particular) are still a common benchmark today. * FLOPs is very difficult to calculate in theory because modern CPU…
> 'The' flop is a misnomer because it's almost always the multiply-and-accumulate instruction: X = A + B * C. Which... Is two operations per instruction (per shader/SIMD lane). Eeehhh whatever. Who cares about these details?
If FMA is supported, it can either be counted as one or two operations, depending on the rule of the benchmark involved or the marketing of the processor. The marketing specification of a processor's theoretical peak performance sometimes counts a single-instruction FMA as two operations. On the other hand, for the purpose of code profiling, counting FMA as one operation is more realistic... As you said, who cares about these details?