Date: Sat, 31 May 2014 02:53:16 +0200 From: Willem Jan Withagen <wjw@digiware.nl> To: Peter Grehan <grehan@freebsd.org> Cc: freebsd-virtualization@freebsd.org Subject: Re: Bheve: Slow linux syscalls on AMD Message-ID: <538927FC.3000903@digiware.nl> In-Reply-To: <53891EAA.8040105@freebsd.org> References: <5388B56D.1000501@digiware.nl> <20140530212900.6B74B6BF@hub.freebsd.org> <53891BC1.9050701@digiware.nl> <53891EAA.8040105@freebsd.org>
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On 31-5-2014 2:13, Peter Grehan wrote: > Hi Willem, > >> So the question remains: >> Why is it taking so long on the AMD platform. > > The time difference looks a lot like a VM-exit roundtrip. My new AMD > box is arriving shortly so I'll have a look into it. Before running the getuid test: vm exits due to interrupt window opening 0 vm exits due to nmi window opening 0 vm exits due to nested page fault 311094 vm exits for instruction emulation 159415683 number of vm exits for unknown reason 0 number of vm exits handled in userspace 0 number of vm exits due to exceptions 0 total number of vm exits 353767137 vm exits due to external interrupt 177525597 Then calling getuid() 10^6 times vm exits due to interrupt window opening 0 vm exits due to nmi window opening 0 vm exits due to nested page fault 311094 vm exits for instruction emulation 159589889 number of vm exits for unknown reason 0 number of vm exits handled in userspace 0 number of vm exits due to exceptions 0 total number of vm exits 354157461 vm exits due to external interrupt 177730908 And that gives a difference of: 390324 Which is not the regular amount of vm exits counted in the equal idle time. So there seems to be some relation, but it is not 1:1... --WjW
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