Lines Matching +full:burst +full:- +full:length

7    The SCHED_RT case is covered in Documentation/scheduler/sched-rt-group.rst
14 microseconds of CPU time. That quota is assigned to per-cpu run queues in
22 is transferred to cpu-local "silos" on a demand basis. The amount transferred
25 Burst feature
26 -------------
30 Traditional (UP-EDF) bandwidth control is something like:
40 The burst feature observes that a workload doesn't always executes the full
62 The interferenece when using burst is valued by the possibilities for
66 https://lore.kernel.org/lkml/5371BD36-55AE-4F71-B9D7-B86DC32E3D2B@linux.alibaba.com/
69 ----------
70 Quota, period and burst are managed within the cpu subsystem via cgroupfs.
75    :ref:`Documentation/admin-guide/cgroup-v2.rst <cgroup-v2-cpu>`.
77 - cpu.cfs_quota_us: run-time replenished within a period (in microseconds)
78 - cpu.cfs_period_us: the length of a period (in microseconds)
79 - cpu.stat: exports throttling statistics [explained further below]
80 - cpu.cfs_burst_us: the maximum accumulated run-time (in microseconds)
85 	cpu.cfs_quota_us=-1
88 A value of -1 for cpu.cfs_quota_us indicates that the group does not have any
90 bandwidth group. This represents the traditional work-conserving behavior for
95 period is 1ms. There is also an upper bound on the period length of 1s.
112 --------------------
113 For efficiency run-time is transferred between the global pool and CPU local
123 for more fine-grained consumption.
126 ----------
131 - nr_periods: Number of enforcement intervals that have elapsed.
132 - nr_throttled: Number of times the group has been throttled/limited.
133 - throttled_time: The total time duration (in nanoseconds) for which entities
135 - nr_bursts: Number of periods burst occurs.
136 - burst_time: Cumulative wall-time (in nanoseconds) that any CPUs has used
139 This interface is read-only.
142 ---------------------------
144 attainable, that is: max(c_i) <= C. However, over-subscription in the
145 aggregate case is explicitly allowed to enable work-conserving semantics
162 ---------------------------
169 The fact that cpu-local slices do not expire results in some interesting corner
174 quota as well as the entirety of each cpu-local slice in each period. As a
178 For highly-threaded, non-cpu bound applications this non-expiration nuance
179 allows applications to briefly burst past their quota limits by the amount of
181 1ms per cpu or as defined by min_cfs_rq_runtime).  This slight burst only
183 in previous periods. This burst amount will not be transferred between cores.
186 also limits the burst ability to no more than 1ms per cpu.  This provides
192 possibility of wastefully expiring quota on cpu-local silos that don't need a
195 The interaction between cpu-bound and non-cpu-bound-interactive applications
197 gave each of these applications half of a cpu-core and they both got scheduled
198 on the same CPU it is theoretically possible that the non-cpu bound application
200 cpu-bound application from fully using its quota by that same amount. In these
201 instances it will be up to the CFS algorithm (see sched-design-CFS.rst) to
207 --------
216 2. Limit a group to 2 CPUs worth of runtime on a multi-CPU machine
224 	The larger period here allows for increased burst capacity.
234    response at the expense of burst capacity.
240    And 10ms burst will be equivalent to 20% of 1 CPU::
244 	# echo 10000 > cpu.cfs_burst_us /* burst = 10ms */
246    Larger buffer setting (no larger than quota) allows greater burst capacity.