1.
"nmi_watchdog"출처 : http://lists.us.dell.com/pipermail/linux-poweredge/2011-June/044916.html
2.
"Dell PE server power management , handled by the BIOS, certainly does use PMU counter"
출처 : https://lkml.org/lkml/2010/9/3/287
1. perf : the good, the bad, the ugly
출처 : http://rhaas.blogspot.co.uk/2012/06/perf-good-bad-ugly.html
2. oprofile vs perf
출처 : http://comments.gmane.org/gmane.linux.oprofile/11429
OProfile was, arguably, the profiling tool of choice for Linux developers for nearly 10 years. A few years
ago, various members of the Linux kernel community defined and implemented a formal kernel API to access
performance monitor counters (PMCs) to address the needs of the performance tools development
community. Prior to the introduction of this API, oprofile used a special oprofile-specific kernel
module, while other performance tools relied on kernel patches (e.g., 'perfctr', 'perfmon' -- which
were never accepted upstream) to access the PMCs. The kernel developers of this new API also developed an
example tool that used the new API, which they called 'perf'. The original perf tool was capable of
profiling (single process or system-wide), as well as simple event counting. Several
other features have been added to it since then. The perf tool has matured a lot in the past few years, and has
gained a lot of followers.
Currently, oprofile is strictly a profiling tool. So there are more features available in the perf tool,
but with those added features, comes added complexity in using it. Comparing the profiling capabilities
of the two tools, there is a lot of overlap, but they each have their own strengths. The original oprofile
("legacy" opcontrol-based profiler) could only do system-wide profiling, which required root
authority. In August 2012, oprofile 0.9.8 was released that included the new 'operf' tool, which uses the
new kernel API mentioned above. Using operf allows users who know and love oprofile's post-processing
tools to get the same benefits as 'perf' (i.e., single app profiling without the need for root authority),
while still leveraging the advantages of oprofile (symbolic native even
t names, Java profiling, user manual, and an established community).
In the end, though, which of these tools to use for profiling is a personal choice. Try them both out and
decide for yourself. You may find that you'd like to have them both in your toolbox.
