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Johannes Weiner b05e75d611 psi: Fix cpu.pressure for cpu.max and competing cgroups
For simplicity, cpu pressure is defined as having more than one
runnable task on a given CPU. This works on the system-level, but it
has limitations in a cgrouped reality: When cpu.max is in use, it
doesn't capture the time in which a task is not executing on the CPU
due to throttling. Likewise, it doesn't capture the time in which a
competing cgroup is occupying the CPU - meaning it only reflects
cgroup-internal competitive pressure, not outside pressure.

Enable tracking of currently executing tasks, and then change the
definition of cpu pressure in a cgroup from

	NR_RUNNING > 1

to

	NR_RUNNING > ON_CPU

which will capture the effects of cpu.max as well as competition from
outside the cgroup.

After this patch, a cgroup running `stress -c 1` with a cpu.max
setting of 5000 10000 shows ~50% continuous CPU pressure.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200316191333.115523-2-hannes@cmpxchg.org
2020-03-20 13:06:18 +01:00
arch arm64: defconfig: enable CONFIG_SCHED_SMT 2020-03-06 12:57:23 +01:00
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Documentation sched/fair: Enable tuning of decay period 2020-03-06 12:57:21 +01:00
drivers thermal/cpu-cooling, sched/core: Move the arch_set_thermal_pressure() API to generic scheduler code 2020-03-06 14:26:31 +01:00
fs five small cifs/smb3 fixes, two for stable 2020-03-03 17:31:19 -06:00
include psi: Fix cpu.pressure for cpu.max and competing cgroups 2020-03-20 13:06:18 +01:00
init sched/pelt: Add support to track thermal pressure 2020-03-06 12:57:17 +01:00
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kernel psi: Fix cpu.pressure for cpu.max and competing cgroups 2020-03-20 13:06:18 +01:00
lib sched/core: Distribute tasks within affinity masks 2020-03-20 13:06:18 +01:00
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Makefile Linux 5.6-rc4 2020-03-01 16:38:46 -06:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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There are various text files in the Documentation/ subdirectory,
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Please read the Documentation/process/changes.rst file, as it contains the
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