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Subject: Re: [PATCH] pgo: rename the raw profile file to vmlinux.profraw
To:     Bill Wendling <morbo@google.com>, Kees Cook <keescook@google.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Masahiro Yamada <masahiroy@kernel.org>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Nick Desaulniers <ndesaulniers@google.com>
References: <20210531202044.426578-1-morbo@google.com>
From:   Nathan Chancellor <nathan@kernel.org>
Message-ID: <e22afde4-e312-4589-cf2e-3c35219d7249@kernel.org>
Date:   Mon, 31 May 2021 13:29:36 -0700
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On 5/31/2021 1:20 PM, Bill Wendling wrote:
> Future PGO features may create other files in /sys/kernel/debug/pgo. So
> rename the kernel's raw profile data file to "vmlinux.profraw" to make
> which part of the kernel the file is for more explicit.
> 
> Note that future files in /sys/kernel/debug/pgo should follow a similar
> naming convention.
> 
> Signed-off-by: Bill Wendling <morbo@google.com>

Guess this clears up my confusion around the module patches :)

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
>   Documentation/dev-tools/pgo.rst | 6 +++---
>   kernel/pgo/Kconfig              | 7 ++++---
>   kernel/pgo/fs.c                 | 2 +-
>   3 files changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/dev-tools/pgo.rst b/Documentation/dev-tools/pgo.rst
> index b7f11d8405b7..0200449c4843 100644
> --- a/Documentation/dev-tools/pgo.rst
> +++ b/Documentation/dev-tools/pgo.rst
> @@ -76,7 +76,7 @@ The PGO kernel support creates the following files in debugfs:
>   ``/sys/kernel/debug/pgo/reset``
>   	Global reset file: resets all coverage data to zero when written to.
>   
> -``/sys/kernel/debug/profraw``
> +``/sys/kernel/debug/pgo/vmlinux.profraw``
>   	The raw PGO data that must be processed with ``llvm_profdata``.
>   
>   
> @@ -108,7 +108,7 @@ using the result to optimize the kernel:
>   
>      .. code-block:: sh
>   
> -      $ cp -a /sys/kernel/debug/pgo/profraw /tmp/vmlinux.profraw
> +      $ cp -a /sys/kernel/debug/pgo/vmlinux.profraw /tmp/vmlinux.profraw
>   
>   5) (Optional) Download the raw profile data to the HOST machine.
>   
> @@ -120,7 +120,7 @@ using the result to optimize the kernel:
>   
>      Note that multiple raw profile data files can be merged during this step.
>   
> -7) Rebuild the kernel using the profile data (PGO disabled)
> +7) Rebuild the kernel using the processed profile data (PGO disabled)
>   
>      .. code-block:: sh
>   
> diff --git a/kernel/pgo/Kconfig b/kernel/pgo/Kconfig
> index 76a640b6cf6e..d2053df1111c 100644
> --- a/kernel/pgo/Kconfig
> +++ b/kernel/pgo/Kconfig
> @@ -17,10 +17,11 @@ config PGO_CLANG
>   
>   	  Run a representative workload for your application on a kernel
>   	  compiled with this option and download the raw profile file from
> -	  /sys/kernel/debug/pgo/profraw. This file needs to be processed with
> -	  llvm-profdata. It may be merged with other collected raw profiles.
> +	  /sys/kernel/debug/pgo/vmlinux.profraw. This file needs to be
> +	  processed with llvm-profdata. It may be merged with other collected
> +	  raw profiles.
>   
> -	  Copy the resulting profile file into vmlinux.profdata, and enable
> +	  Copy the processed profile file into vmlinux.profdata, and enable
>   	  KCFLAGS=-fprofile-use=vmlinux.profdata to produce an optimized
>   	  kernel.
>   
> diff --git a/kernel/pgo/fs.c b/kernel/pgo/fs.c
> index 449f16beb2cf..ef985159dad3 100644
> --- a/kernel/pgo/fs.c
> +++ b/kernel/pgo/fs.c
> @@ -365,7 +365,7 @@ static int __init pgo_init(void)
>   	if (!directory)
>   		goto err_remove;
>   
> -	if (!debugfs_create_file("profraw", 0600, directory, NULL,
> +	if (!debugfs_create_file("vmlinux.profraw", 0600, directory, NULL,
>   				 &prf_fops))
>   		goto err_remove;
>   
>