Re: [linus:master] [xfs] 2edf06a50f: fsmark.files_per_sec -5.7% regression

From: Dave Chinner
Date: Tue May 09 2023 - 02:55:35 EST


On Tue, May 09, 2023 at 10:13:19AM +0800, kernel test robot wrote:
>
>
> Hello,
>
> kernel test robot noticed a -5.7% regression of fsmark.files_per_sec on:
>
>
> commit: 2edf06a50f5bbe664283f3c55c480fc013221d70 ("xfs: factor xfs_alloc_vextent_this_ag() for _iterate_ags()")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

This is just a refactoring patch and doesn't change any logic.
Hence I'm sceptical that it actually resulted in a performance
regression. Indeed, the profile indicates a significant change of
behaviour in the allocator and I can't see how the commit above
would cause anything like that.

Was this a result of a bisect? If so, what were the original kernel
versions where the regression was detected?

Cheers,

Dave.

--
Dave Chinner
david@xxxxxxxxxxxxx