From f5a15f04746cd2f217ae5e7f2f3aeb42ba9270b0 Mon Sep 17 00:00:00 2001 From: Sage Weil Date: Wed, 23 Nov 2016 17:05:37 -0500 Subject: [PATCH] doc/dev/perf: a few notes on perf and flame graphs Signed-off-by: Sage Weil --- doc/dev/perf.rst | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 doc/dev/perf.rst diff --git a/doc/dev/perf.rst b/doc/dev/perf.rst new file mode 100644 index 0000000000000..6fc7d7ed476bf --- /dev/null +++ b/doc/dev/perf.rst @@ -0,0 +1,39 @@ +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 each top function):: + + sudo perf report --call-graph callee + +:note: If the 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 -- 2.47.3