[Xen-devel] [PATCH 0/7] get rid of the SEDF scheduler

[Dario Faggioli <dario.faggioli@xxxxxxxxxx>]

Hi everyone,

This series is the follow up of this proposal and conversation:
http://lists.xen.org/archives/html/xen-devel/2015-05/msg02874.html

Let me quote this (again), from 2006:
  git show db51cd09d37ea44b126bb259f9392248afd768e6
  ...
  diff --git a/docs/src/interface.tex b/docs/src/interface.tex
  index c9017c7..9a59840 100644
  --- a/docs/src/interface.tex
  +++ b/docs/src/interface.tex
  @@ -209,8 +209,8 @@ implement timeout values when they block.

   Xen offers a uniform API for CPU schedulers.  It is possible to choose
   from a number of schedulers at boot and it should be easy to add more.
  -The SEDF, BVT, and Credit schedulers are part of the normal Xen
  -distribution.  BVT and SEDF will be going away and their use should be
  +The SEDF and Credit schedulers are part of the normal Xen
  +distribution.  SEDF will be going away and its use should be
   avoided once the credit scheduler has stabilized and become the default.
   The Credit scheduler provides proportional fair shares of the
   host's CPUs to the running domains. It does this while transparently

So, after being "going away" for 9 years, here we are, getting rid of it!
Hopefully, I've killed every sign of it, and did not overlook anything.

I'm not sure whether the python bindings are an interface that we consider
stable. I've killed everything about SEDF from there, but I don't know sure how
to test this. If I should do it differently, let me know.

In libxl, I left the symbols and the data types in place, for the sake of
build-time backward compatibility, but any attempt of calling one of the
scheduler API function with LIBXL_SCHEDULED_SEDF as the scheduler id, results
in an error.

As far as testing goes, I have verified that:
 - the repo builds, both xen and tools, at each stage of the series
 - booting with sched=sedf no longer works
 - with all the series applied, `xl sched-sedf' no longer exists
 - with the libxl+libxc patches patch applied (so, with SEDF still available in 
Xen
   and xl), `xl sched-sedf' exists, but produces an error

There is an OSSTest patch that shuts down SEDF testing for xen-unstable
(actually, for everything greater than xen-4.5) here:
http://lists.xen.org/archives/html/xen-devel/2015-06/msg04399.html

Regards,
Dario
---
Dario Faggioli (7):
      libxl: get rid of the SEDF scheduler
      tools: python: get rid of the SEDF scheduler bindings
      libxc: get rid of the SEDF scheduler
      xen: get rid of the SEDF scheduler
      xen: kill sched_sedf.c
      xl: get rid of the SEDF scheduler
      docs: get rid of the SEDF scheduler

 docs/INDEX                              |    1 
 docs/man/xl.cfg.pod.5                   |   24 
 docs/man/xl.pod.1                       |   42 -
 docs/man/xlcpupool.cfg.pod.5            |    4 
 docs/misc/sedf_scheduler_mini-HOWTO.txt |   44 -
 docs/misc/xen-command-line.markdown     |    2 
 tools/examples/cpupool                  |    2 
 tools/libxc/Makefile                    |    1 
 tools/libxc/include/xenctrl.h           |   12 
 tools/libxc/xc_sedf.c                   |   78 --
 tools/libxl/libxl.c                     |   73 -
 tools/libxl/libxl_create.c              |   61 -
 tools/libxl/xl.h                        |    1 
 tools/libxl/xl_cmdimpl.c                |  139 ---
 tools/libxl/xl_cmdtable.c               |   16 
 tools/python/xen/lowlevel/xc/xc.c       |   70 -
 xen/common/Makefile                     |    1 
 xen/common/sched_sedf.c                 | 1556 -------------------------------
 xen/common/schedule.c                   |    1 
 xen/include/public/domctl.h             |    8 
 xen/include/public/trace.h              |    1 
 xen/include/xen/sched-if.h              |    1 
 22 files changed, 7 insertions(+), 2131 deletions(-)
 delete mode 100644 docs/misc/sedf_scheduler_mini-HOWTO.txt
 delete mode 100644 tools/libxc/xc_sedf.c
 delete mode 100644 xen/common/sched_sedf.c

--
<<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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