ia64/xen-unstable
changeset 10208:6d476981e3a5
Update docs for new credit scheduler and cleanup out of date scheduler stuff.
Signed-off-by: Emmanuel Ackaouy <ack@xensource.com>
Signed-off-by: Emmanuel Ackaouy <ack@xensource.com>
author | ack@kneesa.uk.xensource.com |
---|---|
date | Sun May 28 15:49:17 2006 +0100 (2006-05-28) |
parents | 444abe25611f |
children | d5f98d23427a |
files | docs/src/interface.tex docs/src/user.tex |
line diff
1.1 --- a/docs/src/interface.tex Sun May 28 09:46:30 2006 +0100 1.2 +++ b/docs/src/interface.tex Sun May 28 15:49:17 2006 +0100 1.3 @@ -205,30 +205,23 @@ event sent at a specified system time by 1.4 implement timeout values when they block. 1.5 1.6 1.7 - 1.8 -%% % akw: demoting this to a section -- not sure if there is any point 1.9 -%% % though, maybe just remove it. 1.10 - 1.11 -% KAF: Remove these random sections! 1.12 -\begin{comment} 1.13 \section{Xen CPU Scheduling} 1.14 1.15 Xen offers a uniform API for CPU schedulers. It is possible to choose 1.16 from a number of schedulers at boot and it should be easy to add more. 1.17 -The BVT, Atropos and Round Robin schedulers are part of the normal Xen 1.18 -distribution. BVT provides proportional fair shares of the CPU to the 1.19 -running domains. Atropos can be used to reserve absolute shares of 1.20 -the CPU for each domain. Round-robin is provided as an example of 1.21 -Xen's internal scheduler API. 1.22 +The SEDF, BVT, and Credit schedulers are part of the normal Xen 1.23 +distribution. BVT and SEDF will be going away and their use should be 1.24 +avoided once the credit scheduler has stabilized and become the default. 1.25 +The Credit scheduler provides proportional fair shares of the 1.26 +host's CPUs to the running domains. It does this while transparently 1.27 +load balancing runnable VCPUs across the whole system. 1.28 1.29 \paragraph*{Note: SMP host support} 1.30 -Xen has always supported SMP host systems. Domains are statically 1.31 -assigned to CPUs, either at creation time or when manually pinning to 1.32 -a particular CPU. The current schedulers then run locally on each CPU 1.33 -to decide which of the assigned domains should be run there. The 1.34 -user-level control software can be used to perform coarse-grain 1.35 -load-balancing between CPUs. 1.36 -\end{comment} 1.37 +Xen has always supported SMP host systems. When using the credit scheduler, 1.38 +a domain's VCPUs will be dynamically moved across physical CPUs to maximise 1.39 +domain and system throughput. VCPUs can also be manually restricted to be 1.40 +mapped only on a subset of the host's physical CPUs, using the pinning 1.41 +mechanism. 1.42 1.43 1.44 %% More information on the characteristics and use of these schedulers
2.1 --- a/docs/src/user.tex Sun May 28 09:46:30 2006 +0100 2.2 +++ b/docs/src/user.tex Sun May 28 15:49:17 2006 +0100 2.3 @@ -1094,6 +1094,36 @@ running domains in \xend's SXP configura 2.4 You can get access to the console of a particular domain using 2.5 the \verb_# xm console_ command (e.g.\ \verb_# xm console myVM_). 2.6 2.7 +\subsection{Domain Scheduling Management Commands} 2.8 + 2.9 +The credit CPU scheduler automatically load balances guest VCPUs 2.10 +across all available physical CPUs on an SMP host. The user need 2.11 +not manually pin VCPUs to load balance the system. However, she 2.12 +can restrict which CPUs a particular VCPU may run on using 2.13 +the \path{xm vcpu-pin} command. 2.14 + 2.15 +Each guest domain is assigned a \path{weight} and a \path{cap}. 2.16 + 2.17 +A domain with a weight of 512 will get twice as much CPU as a 2.18 +domain with a weight of 256 on a contended host. Legal weights 2.19 +range from 1 to 65535 and the default is 256. 2.20 + 2.21 +The cap optionally fixes the maximum amount of CPU a guest will 2.22 +be able to consume, even if the host system has idle CPU cycles. 2.23 +The cap is expressed in percentage of one physical CPU: 100 is 2.24 +1 physical CPU, 50 is half a CPU, 400 is 4 CPUs, etc... The 2.25 +default, 0, means there is no upper cap. 2.26 + 2.27 +When you are running with the credit scheduler, you can check and 2.28 +modify your domains' weights and caps using the \path{xm sched-credit} 2.29 +command: 2.30 + 2.31 +\begin{tabular}{ll} 2.32 +\verb!xm sched-credit -d <domain>! & lists weight and cap \\ 2.33 +\verb!xm sched-credit -d <domain> -w <weight>! & sets the weight \\ 2.34 +\verb!xm sched-credit -d <domain> -c <cap>! & sets the cap 2.35 +\end{tabular} 2.36 + 2.37 2.38 2.39 %% Chapter Domain Configuration 2.40 @@ -1985,7 +2015,7 @@ editing \path{grub.conf}. 2.41 \item [ tbuf\_size=xxx ] Set the size of the per-cpu trace buffers, in 2.42 pages (default 0). 2.43 \item [ sched=xxx ] Select the CPU scheduler Xen should use. The 2.44 - current possibilities are `sedf' (default) and `bvt'. 2.45 + current possibilities are `sedf' (default), `credit', and `bvt'. 2.46 \item [ apic\_verbosity=debug,verbose ] Print more detailed 2.47 information about local APIC and IOAPIC configuration. 2.48 \item [ lapic ] Force use of local APIC even when left disabled by