Re: [PATCH] pack-bitmap: remove trace2 region from hot path

From: Derrick Stolee <derrickstolee@github.com>
Date: Sep 23, 2022, 18:07 UTC
Message-ID: <edf25c5d-06f4-0b91-6773-f4fe7705c2f8@github.com>
In-Reply-To: <xmqq7d1uuh5f.fsf@gitster.g>

On 9/23/2022 1:36 PM, Junio C Hamano wrote:

Show 20 quoted lines

> "Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com> writes:
> 
>>     I noticed this while trying to backport the Abhradeep's lookup table
>>     work into GitHub's fork. Something went wrong in that process, causing
>>     this region to significantly slow down. It turns out that slow down does
>>     not reproduce on current 'master', which is good. I must have missed
>>     something while I was backporting.
>>     
>>     Regardless, the use of trace2_region_enter() here should be removed or
>>     replaced. For the sake of 2.38.0, this simple removal is safe enough.
> 
> Well, not doing this removal is even safer, if we know that it is
> not hurting in the -rc code.  It would be better than breaking our
> tests without knowing ;-)  I am not upset that the patch broke the
> test, by the way.  Compared to things silently breaking without
> surfacing, a loud breakage in tests is a much easier thing to
> handle.
> 
> My test run with the attached just finished, so that's what I am
> going to queue tentatively on top.

Whoops! I'm very sorry for not noticing that there was a test checking for this trace. Your modification makes sense and I'll try to do a more careful replacement of that test, if possible.

Thanks, -Stolee