STINNER Victor added the comment:

Serhiy Storchaka added the comment:
>> * Change the default repeat from 3 to 5 to have a better distribution of 
>> timings. It makes the timeit CLI 66% slower (ex: 1 second instead of 600 
>> ms). That's the price of stable benchmarks :-)
> For now default timeit run takes from 0.8 to 8 sec. Adding yet 5 sec makes a 
> user more angry.

Ah yes, I forgot that timeit uses power of 10 to have a nice looking
"xxx loops". I chose to use power of 2 in the perf module to have
shorter benchmarks, but powers of 2 are displayed as 2^n to remain

>> * Display large number of loops as power of 10 for readability, ex: "10^6" 
>> instead of "1000000". Also accept "10^6" syntax for the --num parameter.
> 10^6 syntax doesn't look Pythonic. And this change breaks third-party scripts 
> that run timeit.

Do you mean scripts parsing the timeit output (stdout)?

>> * Add support for "ns" unit: nanoseconds (10^-9 second)
> Even "pass" takes at least 0.02 usec on my computer. What you want to measure 
> that takes < 1 ns?

IMO 20 ns is more readable than 0.02 usec.

> I think timeit is just wrong tool for this.

Even if timeit is not reliable, it *is* used to benchmark operations
taking less than 1 us.

> The patch also makes a warning about unreliable results output to stdout and 
> always visible. This is yet one compatibility break. Current code allows the 
> user to control the visibility of the warning by the -W Python option, and 
> don't mix the warning with result output.

Oh, I forgot to documen this change. I made it because the old code
displays a surprising ":0: " prefix. I chose to use print instead. I
don't think that it's a common usage to hide the warning using


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