Re: [Xen-devel] [PATCH v6 2/2] xen: move TLB-flush filtering out into populate_physmap during vm creation

[Dongli Zhang <dongli.zhang@xxxxxxxxxx>]

> > This patch implemented parts of TODO left in commit id
> > a902c12ee45fc9389eb8fe54eeddaf267a555c58 (More efficient TLB-flush
> > filtering in alloc_heap_pages()). It moved TLB-flush filtering out into
> > populate_physmap. Because of TLB-flush in alloc_heap_pages, it's very slow
> > to create a guest with memory size of more than 100GB on host with 100+
> > cpus.
> >
> >
> Do you have some actual numbers on how much faster after applying this
> patch?
> 
> This is mostly for writing release note etc, so it is fine if you don't
> have numbers at hand.

I do not have data of upstream version at hand now.  I always tested the
performance of this patchset by backporting it to an Oracle VM based on a
very old Xen version, before I sent out the patchset for review. The
backport just involves: (1) copy & paste code, (2) change bool to bool_t
and (3) change true/false to 1/0.

The test machine has 8 nodes of 2048GB memory and 128 cpu. With this
patchset applied, the time to re-create a VM (with 135GB memory and 12
vcpu) is reduced from 5min to 20s.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel