On Tue, Nov 09, 2021 at 02:42:58PM +0000, Julien Grall wrote: > Hi Roger, > > On 09/11/2021 14:31, Roger Pau Monne wrote: > > This reverts commit 228ab9992ffb1d8f9d2475f2581e68b2913acb88. > > > > Performance analysis has shown that dropping the domctl lock during > > domain destruction greatly increases the contention in the heap_lock, > > thus making parallel destruction of domains slower. > > > > The following lockperf data shows the difference between the current > > code and the reverted one: > > > > lock: 3342357(2.268295505s), block: 3263853(18.556650797s) > > lock: 2788704(0.362311723s), block: 222681( 0.091152276s) > > Thanks for the numbers, this is already an improvement from the reverted. > > Can you also please provide some details on the setup that was used to get > the number? (e.g. how many guests, amount of memory...).
Those are from Dmitry, and are gathered after destroying 5 guests in parallel. Given his previous emails he seems to use 2GB HVM guests for other tests, so I would assume that's the case for the lock profile data also (albeit it's not said explicitly): https://lists.xenproject.org/archives/html/xen-devel/2021-09/msg01515.html I'm not sure it's worth adding this explicitly, as it's not a very complex test case. Probably any attempts to destroy a minimal amount of guests in parallel (5?) will already show the lock contention in the profiling. Thanks, Roger.
