> -----Original Message----- > From: xen-devel-boun...@lists.xen.org [mailto:xen-devel- > boun...@lists.xen.org] On Behalf Of Jan Beulich > Sent: 06 January 2016 09:59 > To: Paul Durrant; Zhang Yu > Cc: Kevin Tian; Wei Liu; Shuai Ruan; Andrew Cooper; xen- > de...@lists.xen.org; Stefano Stabellini; zhiyuan...@intel.com; Ian Jackson; > Keir (Xen.org) > Subject: Re: [Xen-devel] [V9 2/3] Refactor rangeset structure for better > performance. > > >>> On 06.01.16 at 10:46, <paul.durr...@citrix.com> wrote: > >> From: Jan Beulich [mailto:jbeul...@suse.com] > >> Sent: 06 January 2016 08:53 > >> >>> On 31.12.15 at 10:33, <yu.c.zh...@linux.intel.com> wrote: > >> > On 12/21/2015 10:38 PM, Jan Beulich wrote: > >> >>>>> On 15.12.15 at 03:05, <shuai.r...@linux.intel.com> wrote: > >> >>> This patch refactors struct rangeset to base it on the red-black > >> >>> tree structure, instead of on the current doubly linked list. By > >> >>> now, ioreq leverages rangeset to keep track of the IO/memory > >> >>> resources to be emulated. Yet when number of ranges inside one > >> >>> ioreq server is very high, traversing a doubly linked list could > >> >>> be time consuming. With this patch, the time complexity for > >> >>> searching a rangeset can be improved from O(n) to O(log(n)). > >> >>> Interfaces of rangeset still remain the same, and no new APIs > >> >>> introduced. > >> >> > >> >> So this indeed addresses one of the two original concerns. But > >> >> what about the other (resource use due to thousands of ranges > >> >> in use by a single VM)? IOW I'm still unconvinced this is the way > >> >> to go. > >> > > >> > Thank you, Jan. As you saw in patch 3/3, the other concern was solved > >> > by extending the rangeset size, which may not be convictive for you. > >> > But I believe this patch - refactoring the rangeset to rb_tree, does > >> > not only solve XenGT's performance issue, but may also be helpful in > >> > the future, e.g. if someday the rangeset is not allocated in xen heap > >> > and can have a great number of ranges in it. :) > >> > >> I don't follow: Patch 3 makes things worse resource consumption > >> wise, not better. > >> > > > > Yes, it allows the rangeset to grow larger. Would it be better to tie > > emulation rangesets to a specific domain and have the rangeset limits > defined > > for the domain by the toolstack? > > In fact that's what I had suggested in reply to 3/3 at about the same > time as the mail you've replied to here. >
Sounds like the way to go then :-) Paul > Jan > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
