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[Xen-changelog] Update docs for new credit scheduler and cleanup out of

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Subject: [Xen-changelog] Update docs for new credit scheduler and cleanup out of date scheduler stuff.
From: Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>
Date: Sun, 28 May 2006 16:08:11 +0000
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# HG changeset patch
# User ack@xxxxxxxxxxxxxxxxxxxxxxx
# Node ID 6d476981e3a5da8198f726dfb34904d33dea4f40
# Parent  444abe25611f151194e042539bc9c76404cfccbd
Update docs for new credit scheduler and cleanup out of date scheduler stuff.
Signed-off-by: Emmanuel Ackaouy <ack@xxxxxxxxxxxxx>
 docs/src/interface.tex |   29 +++++++++++------------------
 docs/src/user.tex      |   32 +++++++++++++++++++++++++++++++-
 2 files changed, 42 insertions(+), 19 deletions(-)

diff -r 444abe25611f -r 6d476981e3a5 docs/src/interface.tex
--- a/docs/src/interface.tex    Sun May 28 09:46:30 2006 +0100
+++ b/docs/src/interface.tex    Sun May 28 15:49:17 2006 +0100
@@ -205,30 +205,23 @@ implement timeout values when they block
 implement timeout values when they block.
-%% % akw: demoting this to a section -- not sure if there is any point
-%% % though, maybe just remove it.
-% KAF: Remove these random sections!
 \section{Xen CPU Scheduling}
 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 BVT, Atropos and Round Robin schedulers are part of the normal Xen
-distribution.  BVT provides proportional fair shares of the CPU to the
-running domains.  Atropos can be used to reserve absolute shares of
-the CPU for each domain.  Round-robin is provided as an example of
-Xen's internal scheduler API.
+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
+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
+load balancing runnable VCPUs across the whole system.
 \paragraph*{Note: SMP host support}
-Xen has always supported SMP host systems.  Domains are statically
-assigned to CPUs, either at creation time or when manually pinning to
-a particular CPU.  The current schedulers then run locally on each CPU
-to decide which of the assigned domains should be run there. The
-user-level control software can be used to perform coarse-grain
-load-balancing between CPUs.
+Xen has always supported SMP host systems. When using the credit scheduler,
+a domain's VCPUs will be dynamically moved across physical CPUs to maximise
+domain and system throughput. VCPUs can also be manually restricted to be
+mapped only on a subset of the host's physical CPUs, using the pinning
 %% More information on the characteristics and use of these schedulers
diff -r 444abe25611f -r 6d476981e3a5 docs/src/user.tex
--- a/docs/src/user.tex Sun May 28 09:46:30 2006 +0100
+++ b/docs/src/user.tex Sun May 28 15:49:17 2006 +0100
@@ -1093,6 +1093,36 @@ running domains in \xend's SXP configura
 You can get access to the console of a particular domain using 
 the \verb_# xm console_ command  (e.g.\ \verb_# xm console myVM_). 
+\subsection{Domain Scheduling Management Commands}
+The credit CPU scheduler automatically load balances guest VCPUs
+across all available physical CPUs on an SMP host. The user need
+not manually pin VCPUs to load balance the system. However, she
+can restrict which CPUs a particular VCPU may run on using
+the \path{xm vcpu-pin} command.
+Each guest domain is assigned a \path{weight} and a \path{cap}.
+A domain with a weight of 512 will get twice as much CPU as a
+domain with a weight of 256 on a contended host. Legal weights
+range from 1 to 65535 and the default is 256.
+The cap optionally fixes the maximum amount of CPU a guest will
+be able to consume, even if the host system has idle CPU cycles.
+The cap is expressed in percentage of one physical CPU: 100 is
+1 physical CPU, 50 is half a CPU, 400 is 4 CPUs, etc... The
+default, 0, means there is no upper cap.
+When you are running with the credit scheduler, you can check and
+modify your domains' weights and caps using the \path{xm sched-credit}
+\verb!xm sched-credit -d <domain>! & lists weight and cap \\
+\verb!xm sched-credit -d <domain> -w <weight>! & sets the weight \\
+\verb!xm sched-credit -d <domain> -c <cap>! & sets the cap
@@ -1985,7 +2015,7 @@ editing \path{grub.conf}.
 \item [ tbuf\_size=xxx ] Set the size of the per-cpu trace buffers, in
   pages (default 0).  
 \item [ sched=xxx ] Select the CPU scheduler Xen should use.  The
-  current possibilities are `sedf' (default) and `bvt'.
+  current possibilities are `sedf' (default), `credit', and `bvt'.
 \item [ apic\_verbosity=debug,verbose ] Print more detailed
   information about local APIC and IOAPIC configuration.
 \item [ lapic ] Force use of local APIC even when left disabled by

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