(Several filesystem developers have asked that I post this on the
fsdevel as well the ext4 mailing lists.)
I've posted the results of some 3.1-rc2 / 3.0 ext4 scalability
measurements and comparisons on a 48 core x86_64 server at:
http://free.linux.hp.com/~enw/ext4/3.1-rc2
This includes throughput and CPU efficiency graphs for five simple
workloads, the raw data for same, and lockstats as well. The data have
been useful in improving ext4 scalability in the past.
The data cover ext4 filesystems with and without journals. For
reference, ext3, xfs, and btrfs are included as well.
The most notable improvement in this data is a significant scalability
gain for xfs when running the large_file_creates workload (the lockstats
suggest a behavioral change). This was first visible in 3.1-rc1. ext4
remains relatively unchanged.
Dave Chinner has asked that I make some changes to the way I collect xfs
data, and I'll try to address those before I post again.
Thanks,
Eric