Hi, Tristan Is there any plan to add a counter for vcpu migration counting? I want to see the correlation with these patch.
Thanks, Atsushi SAKAI >Le Mercredi 09 Ao〓 2006 13:27, Isaku Yamahata a 馗rit : >> Hi all >Hi > >some comments enclosed. > >> These patches are for performance tuning TAKE 3. >> They are for comment, review and evaluation. >> >> PATCHES: >> - performace counter >> NEW >> - per vcpu vhpt >> - tlb tracking >> - deferred page freeing >> - p2m exposure >> NEW >> >> CHANGES: >> - various bug fixes. >> especially deferred page freeing patch bug. >> It spoiled performance much. >> >> - performance counter >> added performance counter. >> I added these for evaluation of the patches. >> But I think some of them are usefull for normal use. >> Is there any objection for commit? >I think they can be safely commited. > >> - P2M table exposure >> I also included test module for p2m exposure module. >> It showed that p2m conversion with p2m exposure is faster than >> the hypercall conversion at about order 2. >> So I think p2m exposure patch is acceptable. >> >> >> PATCH DETAIL: >> - per vcpu vhpt >> It focuses on vcpu migration between physical cpus. >> With credit scheduler, vcpu is heavily migrated. >> This patch tries to reduce vTLB flush when vcpu is migrated. >Although I have no objection for integrating this patch I have some doubts >about the gain. >If vcpus are heavily migrated, this is a real loss due to caches. >If vcpus are not heavily migrated the gain should be in the noise. >(Of course it depends on the weight!) > >> - tlb tracking >> It forcuses on grant table mapping. >> When page is unmapped, full vTLB flush is necessary. >> By tracking tlb insert on grant mapped page, full vTLB flush >> can be avoided. >> Especially vbd does only DMA, so dom0 doesn't insert tlb entry >> on the grant mapped page. In such case any vTLB flush isn't needed. >> >> - deferred page freeing >> When the page in which tlb insert isn't tracked is unmapped/zapped from >> domain, full vTLB flush is necessary again. >> Balloon driver and grant table page transfer is the case. >> This patch focuses on it. >> It tries to batch freeing/zapping page from domain in order >> to reduce full vTLB flush. >> >> - p2m exposure >> DMA paravirtualization requires the conversion from pseudo physical >> address to machine address. Currently it is done by hypercall. >> This patch tries to reduce the conversion overhead by read-only >> mapping the xen p2m table to domain. > >Thank you for the optimization job. > >Tristan. > >_______________________________________________ >Xen-ia64-devel mailing list >Xen-ia64-devel@lists.xensource.com >http://lists.xensource.com/xen-ia64-devel > _______________________________________________ Xen-ia64-devel mailing list Xen-ia64-devel@lists.xensource.com http://lists.xensource.com/xen-ia64-devel
