Message 365541 - Python tracker

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Author	vstinner
Recipients	Anselmo Melo, bc, mgorny, vstinner, ware
Date	2020-04-02.00:44:08
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1585788249.05.0.124264820797.issue39503@roundup.psfhosted.org>
In-reply-to

Content
Ooooh, I see. I didn't measure the performance of the right header. I re-run a benchmark using the HTTP header (repeat=15): header = 'Basic ' + ', ' * 15 + 'A' Now I see a major performance difference. Comparison between master ("ref") and PR 18284 ("fix"): Mean +- std dev: [ref] 88.9 ms +- 2.4 ms -> [fix] 17.5 us +- 0.7 us: 5083.23x faster (-100%) So the worst case is now way faster: more than 5000x faster! It's even possible to go up to repeat=10**6 characters, it still takes less than 1 seconds: 412 ms +- 19 ms. On the master branch, repeat=20 already takes around 3 seconds... The slowdown is exponential with repeat increase.

Ooooh, I see. I didn't measure the performance of the right header. I re-run a benchmark using the HTTP header (repeat=15):

    header = 'Basic ' + ', ' * 15 + 'A'

Now I see a major performance difference. Comparison between master ("ref") and PR 18284 ("fix"):

Mean +- std dev: [ref] 88.9 ms +- 2.4 ms -> [fix] 17.5 us +- 0.7 us: 5083.23x faster (-100%)

So the worst case is now way faster: more than 5000x faster!

It's even possible to go up to repeat=10**6 characters, it still takes less than 1 seconds: 412 ms +- 19 ms.

On the master branch, repeat=20 already takes around 3 seconds... The slowdown is exponential with repeat increase.

History
Date	User	Action	Args
2020-04-02 00:44:09	vstinner	set	recipients: + vstinner, mgorny, ware, Anselmo Melo, bc
2020-04-02 00:44:09	vstinner	set	messageid: <1585788249.05.0.124264820797.issue39503@roundup.psfhosted.org>
2020-04-02 00:44:09	vstinner	link	issue39503 messages
2020-04-02 00:44:08	vstinner	create