Profiling changed

created

Profiling.md

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+---
+layout: wiki
+title: Profiling
+permalink: /wiki/Profiling/
+---
+
+Profiling
+=========
+
+This is python profiling primer.
+
+For the purpose of this document, `qubes-dev` is name of the domain used for postprocessing profiling stats.
+
+Requirements
+------------
+
+``` {.wiki}
+yum install gprof2dot graphviz
+git clone http://git.woju.eu/qubes/profiling.git
+```
+
+If you profile something on dom0, move `Upload.sh` from repository to dom0:
+
+``` {.wiki}
+mkdir -p ~/profiling
+qvm-run -p qubes-dev 'cat ~/profiling/Upload.sh' > ~/profiling/Upload.sh
+```
+
+Workflow
+--------
+
+### Identify function responsible for some slow action
+
+You have to select area in which you suspect less than optimal performance. If you do not narrow the area, graphs may be unreadable.
+
+### Replace suspect function with probe
+
+Replace
+
+    def foo(self, bar):
+        # function content
+
+with
+
+    def foo(self, *args):
+        profile.runctx('self.real_foo(*args)', globals(), locals(),
+            time.strftime('/home/user/profiling/foo-%Y%m%d-%H%M%S.pstats'))
+
+    def real_foo(self, a, b, c):
+        # function content
+
+### Run application
+
+Beware that some functions may be called often. For example `qubesmanager/main.py:update_table` gets run once per second. This will produce one pstat file per second.
+
+Remember to revert your changes to application afterwards.
+
+### Upload statistics
+
+If you are in dom0:
+
+``` {.wiki}
+cd ~/profiling
+./Upload.sh
+```
+
+### Analyse
+
+``` {.wiki}
+make
+```
+
+For every `${basename}.pstats` this will produce `${basename}.txt` and `${basename}.svg`. SVG contains call graph. Text file contains list of all functions sorted by cumulative execution time. You may also try `make all-png`.
+
+``` {.wiki}
+make index.html
+```
+
+This creates `index.html` with all SVG graphics linked to TXT files. Ready for upload.
+
+``` {.wiki}
+make REMOTE=example.com:public_html/qubes/profiling/ upload
+```