xfs: does mkfs.xfs require fancy switches to get decent performance? (was Tux3 Report: How fast can we fsync?)

[Daniel Phillips]

On Wednesday, April 29, 2015 12:05:26 PM PDT, Mike Galbraith wrote:
> Here's something that _might_ interest xfs folks.
>
> cd git (source repository of git itself)
> make clean
> echo 3 > /proc/sys/vm/drop_caches
> time make -j8 test
>
> ext4    2m20.721s
> xfs     6m41.887s <-- ick
> btrfs   1m32.038s
> tux3    1m30.262s
>
> Testing by Aunt Tilly: mkfs, no fancy switches, mount the thing, test.
>
> Are defaults for mkfs.xfs such that nobody sane uses them, or does xfs
> really hate whatever git selftests are doing this much?

I'm more interested in the fact that we eked out a win :)

Btrfs appears to optimize tiny files by storing them in its big btree,
the equivalent of our itree, and Tux3 doesn't do that yet, so we are a
bit hobbled for a make load. Eventually, that gap should widen.

The pattern I noticed where the write-anywhere designs are beating the
journal designs seems to continue here. I am sure there are exceptions,
but maybe it is a real thing.

Regards,

Daniel