Re: [PATCH v28 0/4] Virtio-balloon: support free page reporting

From: Wei Wang
Date: Sun Feb 25 2018 - 22:58:46 EST


On 02/09/2018 11:14 AM, Michael S. Tsirkin wrote:
On Fri, Feb 09, 2018 at 11:11:39AM +0800, Wei Wang wrote:
On 02/09/2018 03:55 AM, Michael S. Tsirkin wrote:
On Thu, Feb 08, 2018 at 05:50:16PM +0800, Wei Wang wrote:

Details:
Set up a Ping-Pong local live migration, where the guest ceaselessy
migrates between the source and destination. Linux compilation,
i.e. make bzImage -j4, is performed during the Ping-Pong migration. The
legacy case takes 5min14s to finish the compilation. With this
optimization patched, it takes 5min12s.
How is migration time affected in this case?

When the linux compilation workload runs, the migration time (both the
legacy and this optimization case) varies as the compilation goes on. It
seems not easy to give a static speedup number, some times the migration
time is reduced to 33%, sometimes to 50%, it varies, and depends on how much
free memory the system has at that moment. For example, at the later stage
of the compilation, I can observe 5GB memory being used as page cache. But
overall, I can observe obvious improvement of the migration time.


Best,
Wei
You can run multiple tests and give a best, worst and median numbers.


Sorry for my late response (I was on leaves for some other responsibilities).

Here are some more numbers of the live migration time comparison while linux compilation is in progress (probably the average time is more relevant)

average: 52.4% reduction (optimization v.s. legacy = 1242ms v.s. 2611ms)
best: 69.1%
worst: 21.9%


Best,
Wei