Re: [PATCH v2 10/10] plugins: move the more involved plugins to contrib

[Thomas Huth]

On 09/09/2020 13.27, Alex Bennée wrote:
> We have an exploding complexity problem in the testing so lets just
> move the more involved plugins into contrib. tests/plugins still exist
> for the basic plugins that exercise the API. We restore the old
> pre-meson style Makefile for contrib as it also doubles as a guide for
> out-of-tree plugin builds.
> 
> While we are at it add some examples to the documentation and a
> specific plugins build target.
[...]
> diff --git a/docs/devel/tcg-plugins.rst b/docs/devel/tcg-plugins.rst
> index a05990906cc..e079695caf9 100644
> --- a/docs/devel/tcg-plugins.rst
> +++ b/docs/devel/tcg-plugins.rst
> @@ -134,3 +134,145 @@ longer want to instrument the code. This operation is 
> asynchronous
>  which means callbacks may still occur after the uninstall operation is
>  requested. The plugin isn't completely uninstalled until the safe work
>  has executed while all vCPUs are quiescent.
> +
> +Example Plugins
> +===============
> +
> +There are a number of plugins included with QEMU and you are
> +encouraged to contribute them upstream.

s/contribute them/contribute your own plugins/ ?

> There is a `contrib/plugins`
> +directory where they can go.
> +
> +- tests/plugins
> +
> +These are some basic plugins that are used to test and exercise the
> +API during the `make check-tcg` target.
> +
> +- contrib/plugins/hotblocks.c
> +
> +The hotblocks plugin allows you to examine the where hot paths of
> +execution are in your program. Once the program has finished you will
> +get a sorted list of blocks reporting the starting PC, translation
> +count, number of instructions and execution count. This will work best
> +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::
> +
> +  ./aarch64-linux-user/qemu-aarch64 -plugin contrib/plugins/libhotblocks.so 
> -d plugin ./tests/tcg/aarch64-linux-user/sha1

Maybe break long lines with a backslash ?

> +  SHA1=15dd99a1991e0b3826fede3deffc1feba42278e6
> +  collected 903 entries in the hash table
> +  pc, tcount, icount, ecount
> +  0x0000000041ed10, 1, 5, 66087
> +  0x000000004002b0, 1, 4, 66087
> +  ...
> +
> +- contrib/plugins/hotpages.c
> +
> +Similar to hotblocks but this time tracks memory accesses::
> +
> +  ./aarch64-linux-user/qemu-aarch64 -plugin contrib/plugins/libhotpages.so 
> -d plugin ./tests/tcg/aarch64-linux-user/sha1

dito ?

 Thomas