String performance regression from python 3.2 to 3.3

Terry Reedy tjreedy at
Fri Mar 15 01:48:16 CET 2013

On 3/14/2013 7:14 PM, Terry Reedy wrote:
> On 3/14/2013 6:48 AM, rusi wrote:
>> On Mar 14, 11:47 am, Chris Angelico <ros... at> wrote:
>> <snipped>
>>> I expect that Python 3.2 will behave comparably to the 2.6 stats, but
>>> I don't have 3.2s handy - can someone confirm please?
>> I have 3.2 but not 3.3. Can run it later today if no one does.
>> But better if someone with both on the same machine do the comparison.
> The python devs use the microbenchmarks in
> Tools/stringbench/, which covers all string operations, as
> the basis for improving particular string functions. Overall, Unicode is
> nearly as fast as bytes and 3.3 as fast as 3.2. Find/replace is the
> notable exception in stringbench, so it is an anomaly. Other things are
> faster in 3.3.  In selecting the new implementation, the devs also
> considered space and speed gains that do not show up in microbenchmarks.

Links to the readme and code for stringbench can be found here:

Terry Jan Reedy

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