[Xen-devel] [PATCH 0/4] xen: sched: optimize exclusive pinning and soft-affinity checking

[Dario Faggioli <dario.faggioli@xxxxxxxxxx>]

Hello,

This series is a rework of a patch that was, originally, sent as part of a
series (which went in already):

 https://lists.xen.org/archives/html/xen-devel/2017-07/msg02167.html

As it can be seen in the message above, George suggested doing things a little
bit differently, and I agreed. however, that:
- require a bit more of rework than expected, but here we are;
- opened the possibility for even more optimization. :-)

Basically, the effect of the series is that:
1) when a vCPU is exclusively pinned to a pCPU, a lot of checks, while making
   scheduling decisions in Credit1 and Credit2, are skipped (patch 2);
2) the check to see whether or not a vCPU has a soft-affinity that actually
   matters for the scheduling of the vCPU itself, and should be considered is
   optimized and made faster (patch 4).

So, the important bits are in patches 2 and 4, but both patches 1 and 3 are
necessary to make the other twos possible.

Regards,
Dario
---
Dario Faggioli (4):
      xen: sched: introduce 'adjust_affinity' hook.
      xen: sched: optimize exclusive pinning case (Credit1 & 2)
      xen: sched: improve checking soft-affinity
      xen: sched: simplify (and speedup) checking soft-affinity

 xen/arch/x86/dom0_build.c    |    4 +
 xen/common/sched_credit.c    |  114 +++++++++++++++++++++++++++---------------
 xen/common/sched_credit2.c   |   50 ++++++++++++++++--
 xen/common/sched_null.c      |    8 +--
 xen/common/schedule.c        |   67 +++++++++++++++++++------
 xen/include/xen/perfc_defn.h |    1 
 xen/include/xen/sched-if.h   |   16 +++---
 xen/include/xen/sched.h      |    5 ++
 8 files changed, 188 insertions(+), 77 deletions(-)
--
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)

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