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| author | Ed Santiago <santiago@redhat.com> | 2022-08-09 15:02:08 -0600 |
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| committer | Ed Santiago <santiago@redhat.com> | 2022-08-09 16:18:53 -0600 |
| commit | 2bcee9f627b2cd1e3fe588b581aff05821f5841d (patch) | |
| tree | 4a17d840d90e19057a517358986d6587610d2f6f /docs/source/markdown/options/cpu-shares.md | |
| parent | 72679400b0cd7d059f20b2b84ee8b42306ce607a (diff) | |
| download | podman-2bcee9f627b2cd1e3fe588b581aff05821f5841d.tar.gz podman-2bcee9f627b2cd1e3fe588b581aff05821f5841d.tar.bz2 podman-2bcee9f627b2cd1e3fe588b581aff05821f5841d.zip | |
Man pages: refactor common options
Continued. Harder-to-review ones this time.
Signed-off-by: Ed Santiago <santiago@redhat.com>
Diffstat (limited to 'docs/source/markdown/options/cpu-shares.md')
| -rw-r--r-- | docs/source/markdown/options/cpu-shares.md | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/docs/source/markdown/options/cpu-shares.md b/docs/source/markdown/options/cpu-shares.md new file mode 100644 index 000000000..a5aacd2ca --- /dev/null +++ b/docs/source/markdown/options/cpu-shares.md @@ -0,0 +1,35 @@ +#### **--cpu-shares**, **-c**=*shares* + +CPU shares (relative weight). + +By default, all containers get the same proportion of CPU cycles. This +proportion can be modified by changing the container's CPU share weighting +relative to the combined weight of all the running containers. +Default weight is **1024**. + +The proportion will only apply when CPU-intensive processes are running. +When tasks in one container are idle, other containers can use the +left-over CPU time. The actual amount of CPU time will vary depending on +the number of containers running on the system. + +For example, consider three containers, one has a cpu-share of 1024 and +two others have a cpu-share setting of 512. When processes in all three +containers attempt to use 100% of CPU, the first container would receive +50% of the total CPU time. If a fourth container is added with a cpu-share +of 1024, the first container only gets 33% of the CPU. The remaining containers +receive 16.5%, 16.5% and 33% of the CPU. + +On a multi-core system, the shares of CPU time are distributed over all CPU +cores. Even if a container is limited to less than 100% of CPU time, it can +use 100% of each individual CPU core. + +For example, consider a system with more than three cores. +If the container _C0_ is started with **--cpu-shares=512** running one process, +and another container _C1_ with **--cpu-shares=1024** running two processes, +this can result in the following division of CPU shares: + +| PID | container | CPU | CPU share | +| ---- | ----------- | ------- | ------------ | +| 100 | C0 | 0 | 100% of CPU0 | +| 101 | C1 | 1 | 100% of CPU1 | +| 102 | C1 | 2 | 100% of CPU2 | |