Re: svn commit: r345359 - in head/sys/cddl/dev/dtrace: amd64 i386

2019-03-23 Thread Bruce Evans
On Sat, 23 Mar 2019, Bruce Evans wrote: I now have an almost perfect skew measuring program. It has a variance of about 2 cycles. Output on i4790k (only for CPU 0 vs CPU [1-7], since nothing different happens for the general CPU i vs CPU j comparison): XX(min/avg/max/sd) XX |

Re: svn commit: r345359 - in head/sys/cddl/dev/dtrace: amd64 i386

2019-03-22 Thread Bruce Evans
On Thu, 21 Mar 2019, Mark Johnston wrote: On Thu, Mar 21, 2019 at 10:44:49PM +1100, Bruce Evans wrote: On Wed, 20 Mar 2019, Mark Johnston wrote: On Wed, Mar 20, 2019 at 08:20:18PM -0700, Rodney W. Grimes wrote: Author: markj Date: Thu Mar 21 02:52:22 2019 New Revision: 345359 URL:

Re: svn commit: r345359 - in head/sys/cddl/dev/dtrace: amd64 i386

2019-03-21 Thread Warner Losh
On Thu, Mar 21, 2019 at 1:32 PM Mark Johnston wrote: > On Thu, Mar 21, 2019 at 10:44:49PM +1100, Bruce Evans wrote: > > On Wed, 20 Mar 2019, Mark Johnston wrote: > > > > > On Wed, Mar 20, 2019 at 08:20:18PM -0700, Rodney W. Grimes wrote: > > >>> Author: markj > > >>> Date: Thu Mar 21 02:52:22

Re: svn commit: r345359 - in head/sys/cddl/dev/dtrace: amd64 i386

2019-03-21 Thread Mark Johnston
On Thu, Mar 21, 2019 at 10:44:49PM +1100, Bruce Evans wrote: > On Wed, 20 Mar 2019, Mark Johnston wrote: > > > On Wed, Mar 20, 2019 at 08:20:18PM -0700, Rodney W. Grimes wrote: > >>> Author: markj > >>> Date: Thu Mar 21 02:52:22 2019 > >>> New Revision: 345359 > >>> URL:

Re: svn commit: r345359 - in head/sys/cddl/dev/dtrace: amd64 i386

2019-03-21 Thread John Baldwin
On 3/20/19 7:52 PM, Mark Johnston wrote: > Author: markj > Date: Thu Mar 21 02:52:22 2019 > New Revision: 345359 > URL: https://svnweb.freebsd.org/changeset/base/345359 > > Log: > Don't attempt to measure TSC skew when running as a VM guest. > > It simply doesn't work in general since

Re: svn commit: r345359 - in head/sys/cddl/dev/dtrace: amd64 i386

2019-03-21 Thread Bruce Evans
On Thu, 21 Mar 2019, Bruce Evans wrote: On Wed, 20 Mar 2019, Mark Johnston wrote: On Wed, Mar 20, 2019 at 08:20:18PM -0700, Rodney W. Grimes wrote: Author: markj Date: Thu Mar 21 02:52:22 2019 New Revision: 345359 URL: https://svnweb.freebsd.org/changeset/base/345359 Log: Don't attempt to

Re: svn commit: r345359 - in head/sys/cddl/dev/dtrace: amd64 i386

2019-03-21 Thread Bruce Evans
On Wed, 20 Mar 2019, Mark Johnston wrote: On Wed, Mar 20, 2019 at 08:20:18PM -0700, Rodney W. Grimes wrote: Author: markj Date: Thu Mar 21 02:52:22 2019 New Revision: 345359 URL: https://svnweb.freebsd.org/changeset/base/345359 Log: Don't attempt to measure TSC skew when running as a VM

Re: svn commit: r345359 - in head/sys/cddl/dev/dtrace: amd64 i386

2019-03-20 Thread Rodney W. Grimes
> Author: markj > Date: Thu Mar 21 02:52:22 2019 > New Revision: 345359 > URL: https://svnweb.freebsd.org/changeset/base/345359 > > Log: > Don't attempt to measure TSC skew when running as a VM guest. > > It simply doesn't work in general since VCPUs may migrate between > physical cores.

svn commit: r345359 - in head/sys/cddl/dev/dtrace: amd64 i386

2019-03-20 Thread Mark Johnston
Author: markj Date: Thu Mar 21 02:52:22 2019 New Revision: 345359 URL: https://svnweb.freebsd.org/changeset/base/345359 Log: Don't attempt to measure TSC skew when running as a VM guest. It simply doesn't work in general since VCPUs may migrate between physical cores. The approach used

Re: svn commit: r345359 - in head/sys/cddl/dev/dtrace: amd64 i386

2019-03-20 Thread Mark Johnston
On Wed, Mar 20, 2019 at 08:20:18PM -0700, Rodney W. Grimes wrote: > > Author: markj > > Date: Thu Mar 21 02:52:22 2019 > > New Revision: 345359 > > URL: https://svnweb.freebsd.org/changeset/base/345359 > > > > Log: > > Don't attempt to measure TSC skew when running as a VM guest. > > > >