sf00168887: cfs_rq clean backported from Tejun
PPA description
sched/fair: Fix O(nr_cgroups) in load balance path
Currently, rq->leaf_cfs_rq_list is a traversal ordered list of all
live cfs_rqs which have ever been active on the CPU; unfortunately,
this makes update_blocked_averages() O(# total cgroups) which isn't
scalable at all.
This shows up as a small CPU consumption and scheduling latency
increase in the load balancing path in systems with CPU controller
enabled across most cgroups. In an edge case where temporary cgroups
were leaking, this caused the kernel to consume good several tens of
percents of CPU cycles running update_blocked_averages(), each run
taking multiple millisecs.
This patch fixes the issue by taking empty and fully decayed cfs_rqs
off the rq->leaf_cfs_rq_list.
Adding this PPA to your system
You can update your system with unsupported packages from this untrusted PPA by adding ppa:mimi0213kimo/cfs-rq-clean to your system's Software Sources. (Read about installing)
sudo add-apt-repository ppa:mimi0213kimo/cfs-rq-clean
sudo apt update
For questions and bugs with software in this PPA please contact Gavin Guo.
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Overview of published packages
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4.4.0-112.135~14.04.1hf00178886v20180206b0h51a05e6d6e6dhf00178886v20180206b0hca47fc49e267 (Newer version available) | Gavin Guo () |
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