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trevnorris/perf-flame-graph-notes.md

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Quick steps of how to create a flame graph using perf
Raw
perf-flame-graph-notes.md

The prep-script.sh will setup the latest Node and install the latest perf version on your Linux box.

When you want to generate the flame graph, run the following (folder locations taken from install script):

sudo sysctl kernel.kptr_restrict=0
# May also have to do the following:
# (additional reading http://unix.stackexchange.com/questions/14227/do-i-need-root-admin-permissions-to-run-userspace-perf-tool-perf-events-ar )
sudo sysctl kernel.perf_event_paranoid=0

perf record -i -g -e cycles:u -- ~/sources/node/node --perf-basic-prof script.js

perf script | egrep -v "( __libc_start| LazyCompile | v8::internal::| Builtin:| Stub:| LoadIC:|\[unknown\]| LoadPolymorphicIC:)" | sed 's/ LazyCompile:[*~]\?/ /' | ~/sources/FlameGraph/stackcollapse-perf.pl > out.perf-folded

~/sources/FlameGraph/flamegraph.pl out.perf-folded > node-flame.svg

The data munging is to help expose the most important bits. There is still some play that I'm working with, but right now it seems to be working.

Alternatives:

perf script | egrep -v "( __libc_start|node::Start\(| LazyCompile | Builtin:| Stub:| LoadIC:|\[unknown\]| LoadPolymorphicIC:)" | ../FlameGraph/stackcollapse-perf.pl | grep "uv_run" > out.perf-folded

perf script | egrep -v "( __libc_start|node::Start\(| LazyCompile | v8::internal::| Builtin:| Stub:| LoadIC:|\[unknown\]| LoadPolymorphicIC:)" | ../FlameGraph/stackcollapse-perf.pl | grep "uv_run" > out.perf-folded
Raw
prep-script.sh
#!/bin/bash
sh /etc/lsb-release
wget -O - http://llvm.org/apt/llvm-snapshot.gpg.key|sudo apt-key add -
apt-add-repository "deb http://llvm.org/apt/${DISTRIB_CODENAME}/ llvm-toolchain-${DISTRIB_CODENAME} main"
apt-get update
apt-get -y upgrade
apt-get -y install make build-essential linux-tools-common elfutils libelf-dev flex bison libunwind8 libunwind8-dev libaudit-dev libdw-dev binutils-dev libnuma-dev libslang2-dev asciidoc llvm-3.6 clang-3.6 lldb-3.6 libllvm3.6 subversion libc6-dev-i386 libgtk2.0-dev libperl-dev python-dev git tmux nginx gdb apache2-utils
ln -s /usr/bin/clang-3.6 /usr/bin/clang
ln -s /usr/bin/clang++-3.6 /usr/bin/clang++
ln -s /usr/bin/lldb-3.6 /usr/bin/lldb
echo 'export CC=clang' > ~/.bash_aliases
echo 'export CXX=clang++' >> ~/.bash_aliases
echo 'export GYP_DEFINES="clang=1"' >> ~/.bash_aliases
. ~/.bash_aliases
chmod 777 /usr/share/nginx/html
ln -s /usr/share/nginx/html www
mkdir sources
cd sources
wget https://github.com/joyent/node/archive/v0.11.13.tar.gz
tar xvf v0.11.13.tar.gz
rm v0.11.13.tar.gz
mv node-0.11.13 node
cd node
./configure --gdb
make
make install
cd ~/sources
wget https://github.com/brendangregg/FlameGraph/archive/master.tar.gz
tar xvf master.tar.gz
rm master.tar.gz
mv FlameGraph-master FlameGraph
#cd ~/sources
#wget https://www.kernel.org/pub/linux/kernel/v3.x/linux-3.15.6.tar.gz
#tar xvf linux-3.15.6.tar.gz
#rm linux-3.15.6.tar.gz
#cd linux-3.15.6/tools/perf/
#make -f Makefile.perf install prefix=/usr
@trevnorris
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@dignifiedquire Very nice. Thanks for sharing.

@arunoda The reason for nginx is because I found it was the easiest way to view the flamegraphs myself and share them with others (simple as a single URL). Instead of needing to scp/ftp the file down to my box to look at it.

@bjouhier Thanks for the info about the broken XML. Sorry about the .bash_aliases break. I used this script on fresh servers that hadn't been touched yet.

@ryanstevens
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@trevnorris I just tried to do run perf after installing all the dependancies via the setup script. I've experienced the following error both in Ubuntu and Debian.

After running this step

$ perf record -i -g -e cycles:u -- ~/sources/node/node --perf-basic-prof script.js

I receive this

$ Perf session creation failed.

@thlorenz
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@aseemk you can do that with the flamegraph app I created.
Includes instructions on how to get things working on Linux and Mac.

Also removes the LazyCompile for you when you load a map file.

@jlukanta
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jlukanta commented Jan 8, 2015

I encountered the following errors:

E: Unable to locate package llvm-3.6
E: Couldn't find any package by regex 'llvm-3.6'
E: Unable to locate package clang-3.6
E: Couldn't find any package by regex 'clang-3.6'
E: Unable to locate package lldb-3.6
E: Couldn't find any package by regex 'lldb-3.6'
E: Unable to locate package libllvm3.6
E: Couldn't find any package by regex 'libllvm3.6'

It seems that llvm/clang/lldb/libllvm 3.6 packages were removed. To fix this issue, I simply switched to 3.5 packages. Hopefully this will help some people.

@Redsandro
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$ perf script > perf.data.script
[kernel.kallsyms] with build id 9a87d34680d3efd31b5d57f56906d8c2fc38fc5e not found, continuing without symbols
Failed to open /tmp/perf-29438.map, continuing without symbols

What did I miss?

@cantremember
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probably the node --perf-basic-prof part

@Redsandro
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I'm interested in the function calls. There's a lot of module._something, garbage collection and _ZN2v88internal5Scope11LookupLocalEPKNS0_12AstRawStringE stuff in the graph together with function calls. Can I remove all the other stuff and only have the function calls?

@idx3d
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idx3d commented Nov 30, 2016

^^ +1 for the question above. Thx.

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