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author | Carsten Emde <C.Emde@osadl.org> | 2011-07-19 12:53:12 (GMT) |
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committer | Emil Medve <Emilian.Medve@Freescale.com> | 2013-05-26 07:13:37 (GMT) |
commit | 28d29f904b84e29195fb24ecd90b12140660712a (patch) | |
tree | adad75df03672a4d6e2016696bef2e36b673c939 /drivers/misc/Kconfig | |
parent | 84e48c44083c595f40ecf2f9d1ad81b21cc6de03 (diff) | |
download | linux-fsl-qoriq-28d29f904b84e29195fb24ecd90b12140660712a.tar.xz |
hwlatdetect.patch
Jon Masters developed this wonderful SMI detector. For details please
consult Documentation/hwlat_detector.txt. It could be ported to Linux
3.0 RT without any major change.
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Diffstat (limited to 'drivers/misc/Kconfig')
-rw-r--r-- | drivers/misc/Kconfig | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index e94f19d..25ffcfd 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -121,6 +121,35 @@ config IBM_ASM for information on the specific driver level and support statement for your IBM server. +config HWLAT_DETECTOR + tristate "Testing module to detect hardware-induced latencies" + depends on DEBUG_FS + depends on RING_BUFFER + default m + ---help--- + A simple hardware latency detector. Use this module to detect + large latencies introduced by the behavior of the underlying + system firmware external to Linux. We do this using periodic + use of stop_machine to grab all available CPUs and measure + for unexplainable gaps in the CPU timestamp counter(s). By + default, the module is not enabled until the "enable" file + within the "hwlat_detector" debugfs directory is toggled. + + This module is often used to detect SMI (System Management + Interrupts) on x86 systems, though is not x86 specific. To + this end, we default to using a sample window of 1 second, + during which we will sample for 0.5 seconds. If an SMI or + similar event occurs during that time, it is recorded + into an 8K samples global ring buffer until retreived. + + WARNING: This software should never be enabled (it can be built + but should not be turned on after it is loaded) in a production + environment where high latencies are a concern since the + sampling mechanism actually introduces latencies for + regular tasks while the CPU(s) are being held. + + If unsure, say N + config PHANTOM tristate "Sensable PHANToM (PCI)" depends on PCI |