mirror of
https://github.com/QubesOS/qubes-doc.git
synced 2024-10-01 01:25:40 -04:00
99 lines
2.3 KiB
Markdown
99 lines
2.3 KiB
Markdown
---
|
|
lang: en
|
|
layout: doc
|
|
permalink: /doc/profiling/
|
|
redirect_from:
|
|
- /en/doc/profiling/
|
|
- /doc/Profiling/
|
|
- /wiki/Profiling/
|
|
ref: 48
|
|
title: Python profiling
|
|
---
|
|
|
|
This is a python profiling primer.
|
|
|
|
For the purpose of this document, `qubes-dev` is name of the domain used for postprocessing profiling stats.
|
|
|
|
## Requirements
|
|
|
|
~~~
|
|
yum install gprof2dot graphviz
|
|
git clone http://git.woju.eu/qubes/profiling.git
|
|
~~~
|
|
|
|
If you profile something in dom0, move `Upload.sh` from the repository to dom0:
|
|
|
|
~~~
|
|
mkdir -p ~/profiling
|
|
qvm-run -p qubes-dev 'cat ~/profiling/Upload.sh' > ~/profiling/Upload.sh
|
|
~~~
|
|
|
|
- WARNING: this will obviously be running third-party code which is not signed by ITL nor Fedora. You have been warned.
|
|
|
|
## Workflow
|
|
|
|
### Identify function responsible for some slow action
|
|
|
|
You have to select the 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
|
|
|
|
```python
|
|
def foo(self, bar):
|
|
# function content
|
|
```
|
|
|
|
with
|
|
|
|
```python
|
|
def foo(self, *args, **kwargs):
|
|
profile.runctx('self.real_foo(*args, **kwargs)', globals(), locals(),
|
|
time.strftime('/home/user/profiling/foo-%Y%m%d-%H%M%S.pstats'))
|
|
|
|
def real_foo(self, bar):
|
|
# 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 the application afterwards.
|
|
|
|
### Upload statistics
|
|
|
|
If you are in dom0:
|
|
|
|
~~~
|
|
cd ~/profiling
|
|
./Upload.sh
|
|
~~~
|
|
|
|
### Analyse
|
|
|
|
~~~
|
|
make
|
|
~~~
|
|
|
|
For every `${basename}.pstats` this will produce `${basename}.txt` and `${basename}.svg`. SVG files contain call graphs. Text files contain lists of all functions, sorted by cumulative execution time. You may also try `make all-png`.
|
|
|
|
~~~
|
|
make index.html
|
|
~~~
|
|
|
|
This creates `index.html` with all SVG graphics linked to TXT files, ready for upload.
|
|
|
|
~~~
|
|
make REMOTE=example.com:public_html/qubes/profiling/ upload
|
|
~~~
|
|
|
|
## Example
|
|
|
|
This example is from `qubes-manager` (`qubesmanager/main.py`).
|
|
|
|
|
|
|
|
It is apparent that the problem is around `get_disk_usage`, which calls something via `subprocess.call`. It does this 15 times, probably once per VM.
|