Notice

This document is for a development version of Ceph.

Warning

This document is for an unsupported version of Ceph.

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Using perf

Top:

sudo perf top -p `pidof ceph-osd`

To capture some data with call graphs:

sudo perf record -p `pidof ceph-osd` -F 99 --call-graph dwarf -- sleep 60

To view by caller (where you can see what each top function calls):

sudo perf report --call-graph caller

To view by callee (where you can see who calls each top function):

sudo perf report --call-graph callee

note:

If the caller/callee views look the same you may be suffering from a kernel bug; upgrade to 4.8 or later.

Flamegraphs

First, get things set up:

cd ~/src
git clone https://github.com/brendangregg/FlameGraph

Run ceph, then record some perf data:

sudo perf record -p `pidof ceph-osd` -F 99 --call-graph dwarf -- sleep 60

Then generate the flamegraph:

sudo perf script | ~/src/FlameGraph/stackcollapse-perf.pl > /tmp/folded
~/src/FlameGraph/flamegraph.pl /tmp/folded > /tmp/perf.svg
firefox /tmp/perf.svg