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Gmane
From: Jon Masters <jonathan <at> jonmasters.org>
Subject: [PATCH 0/1] Hardware Latency Detector (formerly SMI detector)
Newsgroups: gmane.linux.kernel
Date: Thursday 11th June 2009 04:58:29 UTC (over 7 years ago)
Hi folks,

Please find attached my second re-write of the SMI detector, now called the
Hardware Latency Detector. This is a loadable module that grabs the CPU for
configurable periods of time (all under stop_machine()) and samples the TSC
looking for discontinuity. If observed latencies exceed a threshold (for
example caused by an System Management Interrupt or similar) then the
event is recorded in a global ring_buffer, readable via debugfs.

The previous version was too x86-centric, since there is no reason one
could
not also use this newly renamed hwlat_detector on any supported platform
with
some kind of underlying firmware/virtualization issues effecting observable
system latency measurements.

Thanks to akpm and others for feedback comments so far.

Changes since the previous version:

- Renamed to hwlat_detector
- Followed Andrew's cleanup advice
- Rewritten the documentation

Jon.
 
CD: 3ms