2016-11-23 22:05:37 +00:00
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Using perf
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==========
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Top::
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sudo perf top -p `pidof ceph-osd`
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To capture some data with call graphs::
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sudo perf record -p `pidof ceph-osd` -F 99 --call-graph dwarf -- sleep 60
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To view by caller (where you can see what each top function calls)::
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sudo perf report --call-graph caller
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2016-12-05 11:10:08 +00:00
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To view by callee (where you can see who calls each top function)::
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2016-11-23 22:05:37 +00:00
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sudo perf report --call-graph callee
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2016-12-05 11:10:08 +00:00
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:note: If the caller/callee views look the same you may be
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2016-11-23 22:05:37 +00:00
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suffering from a kernel bug; upgrade to 4.8 or later.
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Flamegraphs
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-----------
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First, get things set up::
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cd ~/src
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git clone https://github.com/brendangregg/FlameGraph
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Run ceph, then record some perf data::
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sudo perf record -p `pidof ceph-osd` -F 99 --call-graph dwarf -- sleep 60
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Then generate the flamegraph::
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sudo perf script | ~/src/FlameGraph/stackcollapse-perf.pl > /tmp/folded
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~/src/FlameGraph/flamegraph.pl /tmp/folded > /tmp/perf.svg
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firefox /tmp/perf.svg
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