Lines Matching refs:stall
3 This document first discusses what sorts of issues RCU's CPU stall
6 this document explains the stall detector's "splat" format.
11 So your kernel printed an RCU CPU stall warning. The next question is
12 "What caused it?" The following problems can result in RCU CPU stall
35 RCU CPU stall warning messages. Especially if you have added
52 memory, you might see stall-warning messages.
60 CONFIG_PREEMPT_RCU case, you might see stall-warning
69 RCU CPU stall warnings.
71 o Testing a workload on a fast system, tuning the stall-warning
72 timeout down to just barely avoid RCU CPU stall warnings, and then
73 running the same workload with the same stall-warning timeout on a
80 result in RCU CPU stall warnings for CONFIG_NO_HZ_COMMON=n kernels.
87 This resulted in a series of RCU CPU stall warnings, eventually
90 The RCU, RCU-sched, RCU-bh, and RCU-tasks implementations have CPU stall
91 warning. Note that SRCU does -not- have CPU stall warnings. Please note
93 No grace period, no CPU stall warnings.
95 To diagnose the cause of the stall, inspect the stack traces.
97 If you have a series of stall warnings from a single extended stall,
98 comparing the stack traces can often help determine where the stall
101 If you can reliably trigger the stall, ftrace can be quite helpful.
111 CPU stall detector, which detects conditions that unduly delay RCU grace
112 periods. This module parameter enables CPU stall detection by default,
114 The stall detector's idea of what constitutes "unduly delayed" is
121 issues an RCU CPU stall warning. This time period is normally
127 So if you are 10 seconds into a 40-second stall, setting this
129 -next- stall, or the following warning for the current stall
130 (assuming the stall lasts long enough). It will not affect the
131 timing of the next warning for the current stall.
141 giving an RCU CPU stall warning message. (This is a cpp
146 The CPU stall detector tries to make the offending CPU print its
148 However, if the offending CPU does not detect its own stall in
156 This boot/sysfs parameter controls the RCU-tasks stall warning
157 interval. A value of zero or less suppresses RCU-tasks stall
158 warnings. A positive value sets the stall-warning interval
159 in jiffies. An RCU-tasks stall warning starts with the line:
178 causing stalls, and that the stall was affecting RCU-sched. This message
182 possible for a rcu_preempt_state stall to be caused by both CPUs -and-
207 across repeated stall-warning messages, it is possible that RCU's softirq
217 The "detected by" line indicates which CPU detected the stall (in this
238 If the grace period ends just as the stall warning starts printing,
239 there will be a spurious stall-warning message, which will include
245 possible for a zero-jiffy stall to be flagged in this case, depending
246 on how the stall warning and the grace-period initialization happen to
252 grace period has nevertheless failed to end, the stall-warning splat
265 the stall warning, as was the case in the "All QSes seen" line above,
271 in RCU CPU stall warnings even when all CPUs and tasks have passed
282 If a stall lasts long enough, multiple stall-warning messages will be
286 of the stall and the first message.
291 If an expedited grace period detects a stall, it will place a message
317 It is entirely possible to see stall warnings from normal and from