I'm usually a fan of Higham, but the last few posts have been weak.
Flops ?
Very witty Wilde ...
What is a flop?
11–20 of 41 posts
Re: What is a flop?
#12My last two startups.
Re: What is a flop?
#13Disappointed this is not about basketball.
Re: What is a flop?
#14Floating Point Operations Per
Re: What is a flop?
#15My last two startups.
You could use it as a unit of accounting for investing losses. A gigaflop would be a loss of 1 billion, etc.
Re: What is a flop?
#16My 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…
> 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)
Actually the origin of this term was VAX MIPS (VAX 780 specifically) because that was a ubiquitous, pretty fast for its time minicomputer. There were faster machines, and slower mainframes still being built, but that was what the late 70s were like.
When the 8051 was released in 1980 it surely didn’t run at 12 MHz! Back then the Z80 sold because it could run 8080 code at a blistering 2 MHz.
BTW the benchmark for FLOPS in those days was Whetstone, hence the otherwise weird name “Dhrystone”
Re: What is a flop?
#17My 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 process…
Given that the point of the FLOPS unit is to compare processors, it does make more sense to count complex instructions as more than a single floating-point operation. If one CPU could multiply a 4x4 matrix by a vector in a single instruction that can run a million times per second, and another CPU needed ~32 instructions and so can only multiply 500k matrices per second but retires 16 million instructions in that same second, it would be silly to compare instructions instead of multiplications and additions.
Re: What is a flop?
#18My 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…
> 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) Actually the origin of this term was VAX MIPS (VAX 780 specifically) because that was a ubiquitous, pretty fast for its time minicomputer. There were faster machines, and slower mainframes still being built, but that was what the late 70s were like. Wh…
The 1981 manual for the 8051 contains numerous references to 12MHz.
http://bitsavers.informatik.uni-stuttgart.de/components/inte...
It was 12T clocked: even though the clock was 12MHz, it would only operate at 1MHz / 1MIPS, because it took 12-clock-ticks to even perform one addition.
IIRC, there was a standard crystal (11.0592 MHz crystal?? I forget exactly) for the communications at the time. So going just above 11 MHz (or really, just above 11.0592 MHz) was needed for reliable serial comms.
Re: What is a flop?
#19this
Re: What is a flop?
#20Earlier quoted context omitted.
> '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 process…
Given that the point of the FLOPS unit is to compare processors, it does make more sense to count complex instructions as more than a single floating-point operation. If one CPU could multiply a 4x4 matrix by a vector in a single instruction that can run a million times per second, and another CPU needed ~32 instructions and so can only multiply 500k matrices per second but retires 16 million instructions in that sam…
As a computer-engineer, the circuit design needed to make a fast multiplication operation (ie: Wallace Tree, and similar) are an order-of-magnitude larger than the circuit design needed for fast addition (ie: a Kogge-Stone Carry lookahead Adder).
This idea that additions and multiplications can be combined like this as "equivalent operations" is kinda bullshit. But hey, if its "how its done" (and its done this way because multiply-then-add is how you do matrix-multiplications...) then so be it.
Just remember that this is an arbitrary subdivision of a matrix multiplication operation, that may not have much relevance as a benchmark outside of matrix multiplications.