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docs/devel: update tcg-plugins page

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Reflect recent changes on API (inline ops) and new plugins.

Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-Id: <20240812231945.169310-1-pierrick.bouvier@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240813202329.1237572-21-alex.bennee@linaro.org>
This commit is contained in:
Pierrick Bouvier 2024-08-13 21:23:28 +01:00 • committed by Alex Bennée
parent 24c32ed374
commit 3f9f9a37ae
2 changed files with 50 additions and 12 deletions
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49
docs/about/emulation.rst
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@ -207,8 +207,8 @@ Once built a program can be run with multiple plugins loaded each with
their own arguments::
$QEMU $OTHER_QEMU_ARGS \
-plugin contrib/plugin/libhowvec.so,inline=on,count=hint \
-plugin contrib/plugin/libhotblocks.so
-plugin contrib/plugins/libhowvec.so,inline=on,count=hint \
-plugin contrib/plugins/libhotblocks.so
Arguments are plugin specific and can be used to modify their
behaviour. In this case the howvec plugin is being asked to use inline
@ -219,6 +219,14 @@ Linux user-mode emulation also evaluates the environment variable
QEMU_PLUGIN="file=contrib/plugins/libhowvec.so,inline=on,count=hint" $QEMU
QEMU plugins avoid to write directly to stdin/stderr, and use the log provided
by the API (see function ``qemu_plugin_outs``).
To show output, you may use this additional parameter::
$QEMU $OTHER_QEMU_ARGS \
-d plugin \
-plugin contrib/plugins/libhowvec.so,inline=on,count=hint
Example Plugins
~~~~~~~~~~~~~~~
@ -260,8 +268,7 @@ Behaviour can be tweaked with the following arguments:
* - Option
- Description
* - inline=true|false
- Use faster inline addition of a single counter. Not per-cpu and not
thread safe.
- Use faster inline addition of a single counter.
* - idle=true|false
- Dump the current execution stats whenever the guest vCPU idles
@ -381,6 +388,15 @@ run::
160 1 0
135 1 0
Test inline operations
......................
``tests/plugins/inline.c``
This plugin is used for testing all inline operations, conditional callbacks and
scoreboard. It prints a per-cpu summary of all events.
Hot Blocks
..........
@ -394,9 +410,6 @@ with linux-user execution as system emulation tends to generate
re-translations as blocks from different programs get swapped in and
out of system memory.
If your program is single-threaded you can use the ``inline`` option for
slightly faster (but not thread safe) counters.
Example::
$ qemu-aarch64 \
@ -736,6 +749,28 @@ The plugin will log the reason of exit, for example::
0xd4 reached, exiting
Limit instructions per second
.............................
This plugin can limit the number of Instructions Per Second that are executed::
# get number of instructions
$ num_insn=$(./build/qemu-x86_64 -plugin ./build/tests/plugin/libinsn.so -d plugin /bin/true |& grep total | sed -e 's/.*: //')
# limit speed to execute in 10 seconds
$ time ./build/qemu-x86_64 -plugin ./build/contrib/plugins/libips.so,ips=$(($num_insn/10)) /bin/true
real 10.000s
.. list-table:: IPS arguments
:widths: 20 80
:header-rows: 1
* - Option
- Description
* - ips=N
- Maximum number of instructions per cpu that can be executed in one second.
The plugin will sleep when the given number of instructions is reached.
Other emulation features
------------------------