Improve perfomance of UUID.hex and UUID.str by using bytes.hex() #131196

booqoffsky · 2025-03-13T16:38:07Z

Feature or enhancement

Proposal:

In my tests, using bytes.hex() speeds up calling the UUID.hex property.

Additionally, using the hex property and f-strings also provides some speedup in calling uuid.UUID.str.

import uuid

uuids = [uuid.uuid4() for _ in range(100000)]

t1 = time.monotonic()
for u in uuids:
    u.hex
    # str(u)
t2 = time.monotonic()

print(t2 - t1)

Results before and after the fix:

hex
before: 0.021755493999989994
after:  0.01465080400066654 

str
before: 0.06381790500017814
after:  0.05134949700004654

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

gh-131196: Improve perfomance of UUID.hex and UUID.__str__ by using bytes.hex() #131197

The text was updated successfully, but these errors were encountered:

picnixz · 2025-03-13T17:00:36Z

In other words, it boils down between whether '%032x' % self.int is faster or not than int->bytes conversion + bytes.hex(). So to really know whether it's faster or not, I would instead check the performances of "%032x" % self.int vs x = self.int.to_bytes(16); x.hex().

Now, I would appreciate benchmarks using timeit or pyperf instead of manual benchmarks. They are a bit more precise and stable (pyperf also shows the standard deviation which is kind of good to know). While it's a noticeable difference overall, we're actually only gaining 10^-8 for each call (since you're doing lots of objects). Finally, are the benchmarks performed on a DEBUG build, release build or optimized (PGO or PGO+LTO) build?

8000

booqoffsky · 2025-03-13T19:29:01Z

Thanks for the answer!

This is how the interpreter was built:

./configure --enable-optimizations --with-lto
make -s -j8

Here are the measurement results:

nice -n 19 taskset -c 4 python3 -m pyperf timeit --affinity=4 --min-time 1 --processes 1 -s 'import uuid; u = uuid.uuid4()' '"%032x" % u.int'
# Mean +- std dev: 70.9 ns +- 0.2 ns

nice -n 19 taskset -c 4 python3 -m pyperf timeit --affinity=4 --min-time 1 --processes 1 -s 'import uuid; u = uuid.uuid4()' 'x = u.int.to_bytes(16); x.hex()'
# Mean +- std dev: 61.1 ns +- 0.3 ns

picnixz · 2025-03-13T19:42:16Z

Mmh. The improvement is a small, but it's still a improvement I guesss. It's still > 10% improvement!

#131197) Results before and after the fix: ``` hex before: 0.021755493999989994 after: 0.01465080400066654 str before: 0.06381790500017814 after: 0.05134949700004654 ``` Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>

sobolevn · 2025-03-13T22:58:49Z

Thank you for the PR! Please, feel free to suggest more optimizations.

…by ~10% (python#131197) Results before and after the fix: ``` hex before: 0.021755493999989994 after: 0.01465080400066654 str before: 0.06381790500017814 after: 0.05134949700004654 ``` Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>

booqoffsky added the type-feature A feature request or enhancement label Mar 13, 2025

bedevere-app bot mentioned this issue Mar 13, 2025

gh-131196: Improve perfomance of UUID.hex and UUID.__str__ by using bytes.hex() #131197

Merged

picnixz added the stdlib Python modules in the Lib dir label Mar 13, 2025

picnixz added the performance Performance or resource usage label Mar 13, 2025

sobolevn closed this as completed Mar 13, 2025

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Improve perfomance of UUID.hex and UUID.str by using bytes.hex() #131196

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Improve perfomance of UUID.hex and UUID.__str__ by using bytes.hex() #131196

Improve perfomance of UUID.hex and UUID.__str__ by using bytes.hex() #131196

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Feature or enhancement

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Improve perfomance of UUID.hex and UUID.str by using bytes.hex() #131196

Improve perfomance of UUID.hex and UUID.str by using bytes.hex() #131196