W dniu 3.07.2023 o 18:57, Richard Earnshaw (lists) pisze:
On 03/07/2023 17:42, Rafał Pietrak via Gcc wrote:
Hi Ian,
[---------]
And WiKi reporting up to 40% performance improvements in some corner
cases is impressive and encouraging. I believe, that the reported
average of 5-8% improvement would be significantly better within MCU
tiny resources environment. In MCU world, such improvement could mean
fit-nofit of a project into a particular device.
-R
I think you need to be very careful when reading benchmarketing (sic)
numbers like this. Firstly, this is a 32-bit vs 64-bit measurement;
secondly, the benchmark (spec 2000) is very old now and IIRC was not
fully optimized for 64-bit processors (it predates the 64-bit version of
the x86 instruction set); thirdly, there are benchmarks in SPEC which
are very sensitive to cache size and the 32-bit ABI just happened to
allow them to fit enough data in the caches to make the numbers leap.
Yes. Sure. I am. I thought I've expressed it clearly, that the
"fantastic 40%" I regard as just "corner case" - those don't usually
reflect ordinary usage.
I was only highlighting the fact, that mare 5-8% improvement can result
on fit-nofit of a particular design into a particular device ... in
consequence requiring to use 4k-RAM device instead of 2k-RAM one.
Tiny improvements of performance of x64 workhorses can become relatively
huge in micros like stm32. That's all.
-R
