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Message-ID: <043b9474f83b2da34bce5ff94b9aa3b735b70d4f.camel@perches.com>
Date: Fri, 14 Oct 2022 07:15:08 -0700
From: Joe Perches <joe@...ches.com>
To: Sasha Levin <sashal@...nel.org>, linux-kernel@...r.kernel.org,
stable@...r.kernel.org
Cc: ye xingchen <ye.xingchen@....com.cn>,
Zeal Robot <zealci@....com.cn>,
Michael Ellerman <mpe@...erman.id.au>, shuah@...nel.org,
linuxppc-dev@...ts.ozlabs.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH AUTOSEL 4.9 1/3] powerpc/selftests: Use timersub() for
gettimeofday()
On Fri, 2022-10-14 at 09:54 -0400, Sasha Levin wrote:
> From: ye xingchen <ye.xingchen@....com.cn>
>
> [ Upstream commit c814bf958926ff45a9c1e899bd001006ab6cfbae ]
>
> Use timersub() function to simplify the code.
Why should a code simplification be backported?
>
> Reported-by: Zeal Robot <zealci@....com.cn>
> Signed-off-by: ye xingchen <ye.xingchen@....com.cn>
> Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
> Link: https://lore.kernel.org/r/20220816105106.82666-1-ye.xingchen@zte.com.cn
> Signed-off-by: Sasha Levin <sashal@...nel.org>
> ---
> tools/testing/selftests/powerpc/benchmarks/gettimeofday.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/powerpc/benchmarks/gettimeofday.c b/tools/testing/selftests/powerpc/benchmarks/gettimeofday.c
> index 3af3c21e8036..7f4bb84f1c9c 100644
> --- a/tools/testing/selftests/powerpc/benchmarks/gettimeofday.c
> +++ b/tools/testing/selftests/powerpc/benchmarks/gettimeofday.c
> @@ -12,7 +12,7 @@ static int test_gettimeofday(void)
> {
> int i;
>
> - struct timeval tv_start, tv_end;
> + struct timeval tv_start, tv_end, tv_diff;
>
> gettimeofday(&tv_start, NULL);
>
> @@ -20,7 +20,9 @@ static int test_gettimeofday(void)
> gettimeofday(&tv_end, NULL);
> }
>
> - printf("time = %.6f\n", tv_end.tv_sec - tv_start.tv_sec + (tv_end.tv_usec - tv_start.tv_usec) * 1e-6);
> + timersub(&tv_start, &tv_end, &tv_diff);
> +
> + printf("time = %.6f\n", tv_diff.tv_sec + (tv_diff.tv_usec) * 1e-6);
>
> return 0;
> }
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