Daniel P. Berrange
2007-Oct-29 19:02 UTC
[Xen-devel] PATCH: Reduce xenstore transactions when listing domains
This is a followup to patches I''ve posted a couple of times before: http://lists.xensource.com/archives/html/xen-devel/2006-10/msg00487.html http://lists.xensource.com/archives/html/xen-devel/2007-04/msg00663.html In summary, this allows a xenstore transaction object to be passed around the various device controllers, so that they don''t have todo lots of singletone transactions. Transactions have very heavy I/O impact from xenstored so reducing their number is important. When running 3 guests, this patch reduces the impact of ''xm list --long'' from 176 transactions, scaling O(n) with guests, to 26 transactions with O(1) scaling. I have previously attempted to also address the same issue with ''xm create'' but that''s much harder since the device front/back handshake requires that XenD use a number of small transactions. So i''ve not changed anything here. I have now been running this patch in Fedora builds of Xen for many months with no reported regressions, so I think its stable enough to be merged now. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=| _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel