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author | H. Peter Anvin <hpa@zytor.com> | 2008-05-31 04:19:03 +0400 |
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committer | H. Peter Anvin <hpa@zytor.com> | 2008-05-31 04:19:03 +0400 |
commit | 23deb06821442506615f34bd92ccd6a2422629d7 (patch) | |
tree | 5e95dba1471007a161e19844fab2d60d422f5423 /Documentation/x86_64/fake-numa-for-cpusets | |
parent | 4039feb5bae72a5fed9ba6bc1a9cfd8dfe0a8613 (diff) | |
download | linux-23deb06821442506615f34bd92ccd6a2422629d7.tar.xz |
x86: move x86-specific documentation into Documentation/x86
The current organization of the x86 documentation makes it appear as
if the "i386" documentation doesn't apply to x86-64, which is does.
Thus, move that documentation into Documentation/x86, and move the
x86-64-specific stuff into Documentation/x86/x86_64 with the eventual
goal to move stuff that isn't actually 64-bit specific back into
Documentation/x86.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'Documentation/x86_64/fake-numa-for-cpusets')
-rw-r--r-- | Documentation/x86_64/fake-numa-for-cpusets | 66 |
1 files changed, 0 insertions, 66 deletions
diff --git a/Documentation/x86_64/fake-numa-for-cpusets b/Documentation/x86_64/fake-numa-for-cpusets deleted file mode 100644 index d1a985c5b00a..000000000000 --- a/Documentation/x86_64/fake-numa-for-cpusets +++ /dev/null @@ -1,66 +0,0 @@ -Using numa=fake and CPUSets for Resource Management -Written by David Rientjes <rientjes@cs.washington.edu> - -This document describes how the numa=fake x86_64 command-line option can be used -in conjunction with cpusets for coarse memory management. Using this feature, -you can create fake NUMA nodes that represent contiguous chunks of memory and -assign them to cpusets and their attached tasks. This is a way of limiting the -amount of system memory that are available to a certain class of tasks. - -For more information on the features of cpusets, see Documentation/cpusets.txt. -There are a number of different configurations you can use for your needs. For -more information on the numa=fake command line option and its various ways of -configuring fake nodes, see Documentation/x86_64/boot-options.txt. - -For the purposes of this introduction, we'll assume a very primitive NUMA -emulation setup of "numa=fake=4*512,". This will split our system memory into -four equal chunks of 512M each that we can now use to assign to cpusets. As -you become more familiar with using this combination for resource control, -you'll determine a better setup to minimize the number of nodes you have to deal -with. - -A machine may be split as follows with "numa=fake=4*512," as reported by dmesg: - - Faking node 0 at 0000000000000000-0000000020000000 (512MB) - Faking node 1 at 0000000020000000-0000000040000000 (512MB) - Faking node 2 at 0000000040000000-0000000060000000 (512MB) - Faking node 3 at 0000000060000000-0000000080000000 (512MB) - ... - On node 0 totalpages: 130975 - On node 1 totalpages: 131072 - On node 2 totalpages: 131072 - On node 3 totalpages: 131072 - -Now following the instructions for mounting the cpusets filesystem from -Documentation/cpusets.txt, you can assign fake nodes (i.e. contiguous memory -address spaces) to individual cpusets: - - [root@xroads /]# mkdir exampleset - [root@xroads /]# mount -t cpuset none exampleset - [root@xroads /]# mkdir exampleset/ddset - [root@xroads /]# cd exampleset/ddset - [root@xroads /exampleset/ddset]# echo 0-1 > cpus - [root@xroads /exampleset/ddset]# echo 0-1 > mems - -Now this cpuset, 'ddset', will only allowed access to fake nodes 0 and 1 for -memory allocations (1G). - -You can now assign tasks to these cpusets to limit the memory resources -available to them according to the fake nodes assigned as mems: - - [root@xroads /exampleset/ddset]# echo $$ > tasks - [root@xroads /exampleset/ddset]# dd if=/dev/zero of=tmp bs=1024 count=1G - [1] 13425 - -Notice the difference between the system memory usage as reported by -/proc/meminfo between the restricted cpuset case above and the unrestricted -case (i.e. running the same 'dd' command without assigning it to a fake NUMA -cpuset): - Unrestricted Restricted - MemTotal: 3091900 kB 3091900 kB - MemFree: 42113 kB 1513236 kB - -This allows for coarse memory management for the tasks you assign to particular -cpusets. Since cpusets can form a hierarchy, you can create some pretty -interesting combinations of use-cases for various classes of tasks for your -memory management needs. |