Re: [platform-testers] [Grep-devel] new snapshot available: grep-2.25.101-be82

[Jim Meyering]

On Tue, Sep 27, 2016 at 1:45 AM, Bruce Dubbs <address@hidden> wrote:
> Jim Meyering wrote:
>>
>> On Mon, Sep 26, 2016 at 8:48 PM, Bruce Dubbs <address@hidden>
>> wrote:
>> ...
>>>>
>>>> regexps. First it times the use of a shorter one, then it times the
>>>> use of a regexp whose byte count is 10 times larger than the first
>>>> one. The test requires that the latter duration be no longer than 20x
>>>> the duration of the first run. In your case, it actually took 80ms
>>>> longer than the 400ms that would be 20x.
>>>>
>>>> As mentioned in its comments, that test is sensitive to load and
>>>> timing. Can you reproduce that failure consistently when running that
>>>> test in isolation? I.e., run this a few times:
>>>>
>>>>     check -C tests TESTS=long-pattern-perf RUN_EXPENSIVE_TESTS=yes
>>>>
>>>> I may end up changing it to run the quick one 5 times, and use the
>>>> minimum time to compare against the duration of the longer-running
>>>> command also being run 5 times (or until passing).
>>>
>>>
>>>
>>> Using the above, I ran it about 6 times and it only passed twice.  I do
>>> have
>>> several apps open but I have 'load average: 0.01, 0.06, 0.05'
>>>
>>> $ free
>>>                total    used    free      shared  buff/cache   available
>>> Mem:        8051948 1724040 5279176      414404     1048732     5834340
>>> Swap:       2097148  361760 1735388
>>
>>
>> Then maybe it's cache effects: much faster with all-in-cache smaller
>> search string.
>> Please see if this patch (quadrupling each regexp size) makes it pass
>> consistently:
>
>
> Yes, the patch makes the test pass consistently on my system, Timing is:

Thanks for confirming. Pushed here:
http://git.sv.gnu.org/cgit/grep.git/commit/?id=0f31cd341971a44371