[Libre-soc-dev] video assembler

Lauri Kasanen cand at gmx.com
Fri May 14 14:44:43 BST 2021

On Fri, 14 May 2021 14:14:31 +0100
Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:

> thus in many ways it is completely misleading to try to use instruction
> counters to guage the performance (more on this below)
> the job of the Vector assembly code is to hit whatever hardware is
> underneath with as much data as it can possibly achieve.
> what *is* therefore useful is to measure the saturation level of each of
> the hardware Function Units, to see if they are 100% occupied, and whether
> anything is stalling out.
> [consequently, hence why i said: if no such assembler exists *that
> iterative feedback analysis process cannot even begin*]
> also what is useful is, once an algorithm has been written, is to see if
> there are better instructions or less instructions that could be used *or
> added to the ISA*, based on an assumption that the "best" hardware
> implementation will ensure 100% throughput without stalls.

Amdahl's law, different approaches to a problem, interleaving
when no hw can rearrange code too far, etc etc. These all apply to SV

I do get what you're trying to say.

- Lauri

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