On Fri, Jul 07, 2006 at 11:46:08AM -0400, Daniel Veillard wrote: > On Fri, Jul 07, 2006 at 03:47:59PM +0100, Daniel P. Berrange wrote: > > Attached is a patch to significantly increase scalability / performance of > > the xenDaemonLookupByID method. The current implementation would get a > > list of all domain names from XenD, and then iterate doing a HTTP GET on > > /xend/domain/[name] until the domain with match ID was found. THis had > > O(n) complexity, with the result that when running on a system with 20 > > actives domains, 'virsh list' would have O(n^2) complexity needing ~230 > > HTTP calls, giving a runtime of ~9 seconds. > > > > The patch is to make the code do a HTTP GET on /xend/domain/[id] which we > > just discovered is a valid URL to access. This makes the method call O(1), > > I should have guessed that earlier, especially after the report > last week about virDomainLookupByName(conn, "1") working fine ... > > > and 'virsh list' is now a saner O(n), and completes in ~1 second. While > > still not great performance, this is certainly much better. I think it > > ought to be possible to optimize the code still further so that XenD is > > avoided altogether for simple commands which can be fullfilled purely > > with data available from Hypervisor, but that will need further > > investigation. > > > > Please review the patch in case I missed any bugs / edge cases > > just 2 small things: > > in xenDaemonLookupByID, it seems (but I may have misread the patch) > that the free of name in the error code in case the rpc failed is a bit > risky and should be guarded by if (name != NULL) Yep, good catch - I missed that check. > and the documentation for the new function in xend_internal.h is the old > one inherited from Anthony first version, I somehow deprecated it, documenting > the function itself in the .c file, but it's just nitpicking :-) Ok, since its all duplicated in the .c file, shall we just rip out all the docs from the xend_internal.h files ? 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 -=|