Overview of performance improvements of recent SMB3 compounding patches

Steve French smfrench at gmail.com
Wed Aug 22 19:28:01 UTC 2018

Continuing the experiments with Ronnie's patches show additional
promising performance results from other common scenarios:

Very good news that the number of roundtrips (request/response pairs
to the server) has dropped so substantially.  Reducing latency, and
allowing the server to more efficiently process the requests leads to
much better performance for these common operations:

- rename goes from 9 request/response pairs to 5 ("mv /mnt/file /mnt/file1")
- hardlink goes from 8 to only 3 (!)  ("ln /mnt/file1 /mnt/file2")
- symlink (with mfsymlinks enabled) goes from 11 to 9 ("ln -s
/mnt/file1 /mnt/file3")
- touch (existing file) 6 down to 4

In current kernel we benefit from compounding now on stafs ("stat -f
/mnt"), and in the earlier note I described the improvements in
create, unlink, mkdir and rmdir which were also awesome.

This is very exciting.

On Tue, Aug 21, 2018 at 1:24 PM Steve French <smfrench at gmail.com> wrote:
> In experiments today with Ronnie's most recent compounding patches I
> see the expected significant improvements in create/mkdir/unlink/rmdir
> operations over SMB3 mounts (tests were to Samba but would be similar
> to all modern servers).  See below:
> "touch /mnt/file"  goes from 6 request/response pairs to 4 with
> Ronnie's compounding patches
> "rm /mnt/file" from 5 to 2 request/response pairs
> "mkdir /mnt/newdir" 6 pairs to 3 pairs
> "rmdir /mnt/newdir" 6 pairs down to 2 pairs
> Good job Ronnie!
> --
> Thanks,
> Steve



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