On Tue, Oct 14, 2014 at 3:24 PM, Amit Kapila <amit.kapil...@gmail.com> wrote: > On Thu, Oct 9, 2014 at 6:17 PM, Amit Kapila <amit.kapil...@gmail.com> wrote: > > On Fri, Sep 26, 2014 at 7:04 PM, Robert Haas <robertmh...@gmail.com> wrote: > > > > > > On another point, I think it would be a good idea to rebase the > > > bgreclaimer patch over what I committed, so that we have a > > > clean patch against master to test with. > > > > Please find the rebased patch attached with this mail. I have taken > > some performance data as well and done some analysis based on > > the same. > > > > > > > > To reduce above contention, I tried to write a patch to replace spin lock > used in dynahash to manage free list by atomic operations. Still there > is work pending for this patch with respect to ensuring whether the > approach used in patch is completely sane, however I am posting the > patch so that others can have a look at it and give me feedback about > the approach.
After further working on this patch (replacement of spinlock in dynahash), I found that I need to solve A-B-A problem for lockless structure as described in section 5.1 of paper [1]. I could have further pursued to solve it by using some additional variables as described in section 5 of paper [1], but it seems to me that Robert has already solved it by using some other technique as proposed by him in patch [2], so it would be waste of effort for me to pursue on this problem. So I am not planning to continue on this patch and marking it as Rejected in CF app. [1] http://www.liblfds.org/mediawiki/images/1/1d/Valois_-_Lock-Free_Linked_Lists_Using_Compare-and-Swap.pdf [2] https://commitfest.postgresql.org/action/patch_view?id=1613 With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
