Re: [PATCH v3 20/29] selftests/resctrl: Replace file write with volatile variable

Reinette Chatre
2023-12-13T21:56:58Z

Hi Ilpo,

On 12/11/2023 4:18 AM, Ilpo Järvinen wrote:
> The fill_buf code prevents compiler optimizating the entire read loop
> away by writing the final value of the variable into a file. While it
> achieves the goal, writing into a file requires significant amount of
> work within the innermost test loop and also error handling.
>
> A simpler approach is to take advantage of volatile. Writing through
> a pointer to a volatile variable is enough to prevent compiler from
> optimizing the write away, and therefore compiler cannot remove the
> read loop either.
>
> Add a volatile 'value_sink' into resctrl_tests.c and make fill_buf to
> write into it. As a result, the error handling in fill_buf.c can be
> simplified.
>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> ---

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Reinette