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workshop1_slides.txt

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+#!/usr/bin/env sent
+
+# install sent with:
+# git clone https://git.suckless.org/sent && cd sent && sudo make install
+
+#Welcome
+
+Choose a server to profile
+- check top for activity
+- open wavefront machine analysis
+- check $(uname -r) before you start
+
+# wget http://www.brendangregg.com/Perf/bcc_tracing_tools.png
+@bcc_tracing_tools.png
+
+# wget http://www.brendangregg.com/BPF/bpf_performance_tools_book.png
+@bpf_performance_tools_book.png
+
+
+\# For linux 4.4+
+sudo perf record -F99 -a -g -- sleep 30
+sudo perf script --header > stacks
+-------------------------------------------------------
+\# For linux 4.9+
+sudo profile -F99 -df 30 > stacks
+
+ctool scp d99-usw-2:stacks .
+git clone https://github.com/brendangregg/FlameGraph.git && cd FlameGraph
+./stackcollapse-perf.pl <stacks >collapsed #ONLY FOR PERF/DTRACE
+./flamegraph.pl <collapsed >flamegraph.svg
+open flamegraph.svg
+
+kernel symbols?
+- sudo apt install linux-image-$(uname -r)-dbgsym
+- echo 0 | sudo tee /proc/sys/kernel/kptr_restrict
+\
+ubuntu package symbols?
+- sudo apt install $(pkgname)-dbgsym
+
+flamescope @ http://10.0.33.119:5000
+
+refining the graphs
+- filter by PID
+- filter a given function call/syscall
+- --color=js,java
+- --color=io
+- c++filt
+\
+./stackcollapse-perf.html < out.stacks | grep do_command | c++filt | \
+    ./flamegraph.pl --color=io --title="Block I/O Flame Graph" --countname="I/O" > out.svg
+
+#see http://www.brendangregg.com/blog/2014-11-09/differential-flame-graphs.html
+"differential" flamegraphs
+./difffolded.pl stacksA stacksB | ./flamegraph.pl > diff_flamegraph.svg
+
+@tsa.png
+
+@offcputracing-1000.png
+
+"off-cpu" flamegraphs (man offcputime)
+-> sudo offcputime -df > stacks
+also hot/cold flamegraphs (on+off cpu)
+
+"wakeup" flamegraphs
+-> sudo wakeuptime -f > stacks