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| author |   Mel Gorman <mgorman@techsingularity.net> | 2020-04-09 11:40:34 +0100 |
|---|---|---|
| committer |   Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-06-05 20:08:26 -0400 |
| commit | 388d8bdb87e01bcea6d0b2bf797b5f6d7b2401fb (patch) | |
| tree | 089b5a342c116668658ef3ea8c5f109840300b2a /kernel/trace/Kconfig | |
| parent | tracing/doc: Fix ascii-art in histogram-design.rst (diff) | |
| download | linux-dev-388d8bdb87e01bcea6d0b2bf797b5f6d7b2401fb.tar.xz linux-dev-388d8bdb87e01bcea6d0b2bf797b5f6d7b2401fb.zip | |
tracing: Remove obsolete PREEMPTIRQ_EVENTS kconfig option
The PREEMPTIRQ_EVENTS option is unused after commit c3bc8fd637a9 ("tracing:
Centralize preemptirq tracepoints and unify their usage"). Remove it.
Note that this option is hazardous as it stands. It enables TRACE_IRQFLAGS
event on non-preempt configurations without the irqsoff tracer enabled.
TRACE_IRQFLAGS as it stands incurs significant overhead on each IRQ
entry/exit. This is because trace_hardirqs_[on|off] does all the per-cpu
manipulations and NMI checks even if tracing is completely disabled for
some insane reason. For example, netperf running UDP_STREAM on localhost
incurs a 4-6% performance penalty without any tracing if IRQFLAGS is
set. It can be put behind a static brach but even the function entry/exit
costs a little bit.
Link: https://lkml.kernel.org/r/20200409104034.GJ3818@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/Kconfig')
| -rw-r--r-- | kernel/trace/Kconfig | 9 |
1 files changed, 0 insertions, 9 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 75407d5dc83a..0c82ac2c5688 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -258,15 +258,6 @@ config TRACE_PREEMPT_TOGGLE Enables hooks which will be called when preemption is first disabled, and last enabled. -config PREEMPTIRQ_EVENTS - bool "Enable trace events for preempt and irq disable/enable" - select TRACE_IRQFLAGS - select TRACE_PREEMPT_TOGGLE if PREEMPTION - select GENERIC_TRACER - default n - help - Enable tracing of disable and enable events for preemption and irqs. - config IRQSOFF_TRACER bool "Interrupts-off Latency Tracer" default n |