Messages in this thread | | | From | riel@redhat ... | Subject | [PATCH -v2 0/2] cpusets,isolcpus: resolve conflict between cpusets and isolcpus | Date | Wed, 25 Feb 2015 11:38:06 -0500 |
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-v2 addresses the conflict David Rientjes spotted between my previous patches and commit e8e6d97c9b ("cpuset: use %*pb[l] to print bitmaps including cpumasks and nodemasks")
Ensure that cpus specified with the isolcpus= boot commandline option stay outside of the load balancing in the kernel scheduler.
Operations like load balancing can introduce unwanted latencies, which is exactly what the isolcpus= commandline is there to prevent.
Previously, simply creating a new cpuset, without even touching the cpuset.cpus field inside the new cpuset, would undo the effects of isolcpus=, by creating a scheduler domain spanning the whole system, and setting up load balancing inside that domain. The cpuset root cpuset.cpus file is read-only, so there was not even a way to undo that effect.
This does not impact the majority of cpusets users, since isolcpus= is a fairly specialized feature used for realtime purposes.
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