Re: [PATCH V4 0/5] x86/mbm : Intel Memory Bandwidth monitoring support

From: Vikas Shivappa
Date: Wed Feb 17 2016 - 13:52:43 EST



Hello Thomas,

Was wondering if you had any feedback on the MBM patches. These are almost a complete rewrite (the core part 3/5 from Tony Luck). The reused parts are mostly the declarations of datastructures. This has tried to address all your comments on V3 about the commenting, the core calculation, init, lot of unnecessary and confusing constants and code..

http://lkml.kernel.org/r/alpine.DEB.2.11.1508192243081.3873@nanos

Thanks,
Vikas

On Wed, 10 Feb 2016, Vikas Shivappa wrote:

The V4 version of MBM is almost a complete rewrite of the prior
versions. It tries to address all of Thomas earlier
comments.

The patch series has one preparatory patch for cqm and then 4 MBM
patches. *Patches apply on 4.5-rc1*.

Memory bandwitdh monitoring(MBM) provides OS/VMM a way to monitor
bandwidth from one level of cache to another. The current patches
support L3 external bandwitch monitoring.
It supports both 'local bandwidth' and 'total bandwidth' monitoring for
the socket. Local bandwidth measures the amount of data sent through
the memory controller on the socket and total b/w measures the total
system bandwidth.

The tasks are associated with a Resouce Monitoring ID(RMID) just like in
cqm and OS uses a MSR write to indicate the RMID of the task during
scheduling.


[PATCH 1/5] x86,perf/cqm : Fix cqm handling of grouping events into a
[PATCH 2/5] x86/mbm: Intel Memory B/W Monitoring enumeration and init
[PATCH 3/5] x86/mbm: Memory bandwidth monitoring event management
[PATCH 4/5] x86/mbm: RMID Recycling MBM changes
[PATCH 5/5] x86/mbm: Add support for MBM counter overflow handling