[Cluster-devel] [PATCH] dlm: fix lowcomms_connect_node for sctp

[Christine Caulfield <ccaulfie@redhat.com>]

On 18/09/09 22:37, David Teigland wrote:
> On Fri, Sep 18, 2009 at 02:39:06PM -0500, David Teigland wrote:
>> The recently added dlm_lowcomms_connect_node() from
>> 391fbdc5d527149578490db2f1619951d91f3561 does not work
>> when using SCTP instead of TCP.  The sctp connection code
>> has nothing to do without data to send.  Check for no data
>> in the sctp connection code and do nothing instead of
>> triggering a BUG.  Also have connect_node() do nothing
>> when the protocol is sctp.

That patch looks sane to me

> With this patch I can use sctp (single interface), but I'm getting these
> alloc_fd errors (which seem harmless enough) have you seen them before?

Yes I have seen them before. At the time I put them down to either a bug 
in SCTP or an artifact of the way it works, because lowcomms isn't 
explicitly allocating any new FDs here - they are hidden behind the sctp 
layer and passed back to use later on in process_sctp_notification().

> Also, gfs is *really* slow using sctp!


I haven't done any benchmarks for ages. The last time some were done I 
was told that SCTP was actually faster than TCP! ... though that was 
with the 'old' DLM. I put this down to the fact that SCTP is optimised 
for streaming because of its origins.

If it's now slowed down a lot it's probably worth investigating further 
- I really wouldn't expect the single-home configurations to differ by 
very much.

Chrissie.