The performance figures in the Python 3.9 "What's New"
Those are also micro-benchmarks, which can have no effect at all on macro-benchmarks. The ones I am linking are almost all macro-benchmarks, so, unfortunately, the ones in Python 3.9 "What's New" are not lying and they seem to be correlated to the same issue.
Also although they are not incorrect, those benchmarks in the Python 3.9 "What's New" were not executed with LTO/PGO/CPU isolation...etc so I would kindly suggest taking the ones in the speed.python.org as the canonical ones if they start to differ in any way.
On Wed, 14 Oct 2020 at 14:25, Paul Moore firstname.lastname@example.org wrote:
The performance figures in the Python 3.9 "What's New" (here - https://docs.python.org/3/whatsnew/3.9.html#optimizations) did look oddly like a lot of things went slower, to me. I assumed I'd misread the figures, and moved on, but maybe I was wrong to do so...
On Wed, 14 Oct 2020 at 14:17, Pablo Galindo Salgado email@example.com wrote:
I have updated the branch benchmarks in the pyperformance server and now
they include 3.9. There are
some benchmarks that are faster but on the other hand some benchmarks
are substantially slower, pointing
at a possible performance regression in 3.9 in some aspects. In
particular some tests like "unpack sequence" are
almost 20% slower. As there are some other tests were 3.9 is faster, is
not fair to conclude that 3.9 is slower, but
this is something we should look into in my opinion.
You can check these benchmarks I am talking about by:
- Go here: https://speed.python.org/comparison/
- In the left bar, select "lto-pgo latest in branch '3.9'" and "lto-pgo
latest in branch '3.8'"
- To better read the plot, I would recommend to select a "Normalization"
to the 3.8 branch (this is in the top part of the page)
and to check the "horizontal" checkbox.
These benchmarks are very stable: I have executed them several times
over the weekend yielding the same results and,
more importantly, they are being executed on a server specially prepared
to running reproducible benchmarks: CPU affinity,
CPU isolation, CPU pinning for NUMA nodes, CPU frequency is fixed, CPU
governor set to performance mode, IRQ affinity is
disabled for the benchmarking CPU nodes...etc so you can trust these
I kindly suggest for everyone interested in trying to improve the 3.9
(and master) performance, to review these benchmarks
and try to identify the problems and fix them or to find what changes
introduced the regressions in the first place. All benchmarks
are the ones being executed by the pyperformance suite (
https://github.com/python/pyperformance) so you can execute them
locally if you need to.
On a related note, I am also working on the speed.python.org server to
provide more automation and
ideally some integrations with GitHub to detect performance regressions.
For now, I have done the following:
- Recompute benchmarks for all branches using the same version of
pyperformance (except master) so they can
be compared with each other. This can only be seen in the
"Comparison" tab: https://speed.python.org/comparison/
- I am setting daily builds of the master branch so we can detect
performance regressions with daily granularity. These
daily builds will be located in the "Changes" and "Timeline" tabs (
- Once the daily builds are working as expected, I plan to work on
trying to automatically comment or PRs or on bpo if
we detect that a commit has introduced some notable performance
Regards from sunny London, Pablo Galindo Salgado. _______________________________________________ python-committers mailing list -- firstname.lastname@example.org To unsubscribe send an email to email@example.com https://mail.python.org/mailman3/lists/python-committers.python.org/ Message archived at
Code of Conduct: https://www.python.org/psf/codeofconduct/