How was the flame graph created? (Not very familiar with C and the performance tools around it)
How we decreased GitLab repo backup times from 48 hours to 41 minutes
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Re: How we decreased GitLab repo backup times from 48 hours to 41 minutes
#12Are there any reimplementations of git, by professional programmers using real tools? The source in question — object.c — is "banging rocks together" material.
Git, but as it was intended to be used
Re: How we decreased GitLab repo backup times from 48 hours to 41 minutes
#13How was the flame graph created? (Not very familiar with C and the performance tools around it)
https://github.com/brendangregg/FlameGraph
You record performance data with `perf`, then use the scripts there to turn it into a SVG.
Re: How we decreased GitLab repo backup times from 48 hours to 41 minutes
#14So they replaced a nested for loop for checking for duplicates with a set data structure. Surprised such a common thing was in git.
Re: How we decreased GitLab repo backup times from 48 hours to 41 minutes
#15"fixed it with an algorithmic change, reducing backup times exponentially" If the backup times were O(n^2), are they now O(n^2 / 2^n)? I would guess not.
Meaningless and non-constructive pedantry.
Re: How we decreased GitLab repo backup times from 48 hours to 41 minutes
#16One of the many reasons I moved to self hosting. I use ZFS to backup every 15 minutes, ... could do it even more frequently but that seems a little pointless.
Also moved away from Gitlab because it's so damn slow.
Re: How we decreased GitLab repo backup times from 48 hours to 41 minutes
#17Duplicate of https://news.ycombinator.com/item?id=44197061
Re: How we decreased GitLab repo backup times from 48 hours to 41 minutes
#18IME, it has always turned out to be the correct decision to eliminate any n^2 operation in anything I’ve written.
I don’t write exotic algorithms, but it’s always astounding how small n needs to be to become observably problematic.
Re: How we decreased GitLab repo backup times from 48 hours to 41 minutes
#19One of the many reasons I moved to self hosting. I use ZFS to backup every 15 minutes, ... could do it even more frequently but that seems a little pointless. Also moved away from Gitlab because it's so damn slow.
ZFS is great, getting off gitlab would also be great, what did you switch to?
Re: How we decreased GitLab repo backup times from 48 hours to 41 minutes
#20looks like the commit is here: https://github.com/git/git/commit/a52d459e72b890c192485002ec...
> * Warning: this function uses an O(N^2) algorithm.