[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] VM memory allocation speed with cs 26056
On 11/12/2012 01:25 PM, Keir Fraser wrote: > On 12/11/2012 15:01, "Zhigang Wang" <zhigang.x.wang@xxxxxxxxxx> wrote: > >> Hi Keir/Jan, >> >> Recently I got a chance to access a big machine (2T mem/160 cpus) and I >> tested >> your patch: http://xenbits.xen.org/hg/xen-unstable.hg/rev/177fdda0be56 >> >> Attached is the result. > The PVM result is weird, there is a small-ish slowdown for small domains, > becoming a very large %age slowdown as domain memory increases, and then > turning into a *speedup* as the memory size gets very large indeed. > > What are the error bars like on these measurements I wonder? One thing we > could do to allow PV guests doing 4k-at-a-time allocations through > alloc_heap_pages() to benefit from the TLB-flush improvements, is pull the > filtering-and-flush out into populate_physmap() and increase_reservation(). > This is listed as a todo in the original patch (26056). > > To be honest I don't know why the original patch would make PV domain > creation slower, and certainly not by a varying %age depending on domain > memory size! > > -- Keir I did it second time. It seems the result (attached) is promising. I think the strange result is due to the order of testing: start_physical_machine -> test_hvm -> test_pvm. This time, I did: start_physical_machine -> test_pvm -> test_hvm. You can see the pvm memory allocation speed is not affected by your patch this time. So I believe this patch is excellent now. Thanks, Zhigang Attachment:
result.pdf _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |