Hi John,
On 5/3/2024 4:40 PM, John Hubbard wrote:
> First of all, in order to build with clang at all, one must first apply
> Valentin Obst's build fix for LLVM [1]. Furthermore, for this particular
> resctrl directory, my pending fix [2] must also be applied. Once those
> fixes are in place, then when building with clang, via:
>
> make LLVM=1 -C tools/testing/selftests
>
> ...two types of warnings occur:
>
> warning: absolute value function 'abs' given an argument of type
> 'long' but has parameter of type 'int' which may cause truncation of
> value
>
> warning: taking the absolute value of unsigned type 'unsigned long'
> has no effect
>
> Fix these by:
>
> a) using labs() in place of abs(), when long integers are involved, and
>
> b) Change to use signed integer data types, in places where subtraction
> is used (and could end up with negative values).
>
> [1]
> https://lore.kernel.org/all/20240329-selftests-libmk-llvm-rfc-v1-1-2f9ed7d1c...@valentinobst.de/
> [2] https://lore.kernel.org/all/20240503021712.78601-1-jhubb...@nvidia.com/
>
> Cc: Reinette Chatre <reinette.cha...@intel.com>
> Signed-off-by: John Hubbard <jhubb...@nvidia.com>
> ---
>
> Hi Reinette,
>
> This v2 includes a fix for the bugs that you pointed out (thanks!) in v1.
>
> I kept the changes to signed integers minimal: only what is required in
> order to get a clean clang build.
>
> thanks,
> John Hubbard
>
> tools/testing/selftests/resctrl/cmt_test.c | 12 ++++++------
> tools/testing/selftests/resctrl/mba_test.c | 4 ++--
> tools/testing/selftests/resctrl/mbm_test.c | 4 ++--
> 3 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/tools/testing/selftests/resctrl/cmt_test.c
> b/tools/testing/selftests/resctrl/cmt_test.c
> index a81f91222a89..af33abd1cca7 100644
> --- a/tools/testing/selftests/resctrl/cmt_test.c
> +++ b/tools/testing/selftests/resctrl/cmt_test.c
> @@ -29,22 +29,22 @@ static int cmt_setup(const struct resctrl_test *test,
> return 0;
> }
>
> -static int show_results_info(unsigned long sum_llc_val, int no_of_bits,
> - unsigned long cache_span, unsigned long max_diff,
> - unsigned long max_diff_percent, unsigned long
> num_of_runs,
> +static int show_results_info(long sum_llc_val, int no_of_bits,
> + long cache_span, long max_diff,
> + long max_diff_percent, long num_of_runs,
> bool platform)
> {
> - unsigned long avg_llc_val = 0;
> + long avg_llc_val = 0;
> float diff_percent;
> long avg_diff = 0;
> int ret;
>
> avg_llc_val = sum_llc_val / num_of_runs;
> - avg_diff = (long)abs(cache_span - avg_llc_val);
> + avg_diff = labs(cache_span - avg_llc_val);
> diff_percent = ((float)cache_span - avg_llc_val) / cache_span * 100;
>
> ret = platform && abs((int)diff_percent) > max_diff_percent &&
> - abs(avg_diff) > max_diff;
> + labs(avg_diff) > max_diff;
>
> ksft_print_msg("%s Check cache miss rate within %lu%%\n",
> ret ? "Fail:" : "Pass:", max_diff_percent);
The changes in this hunk are unexpected. The changes to this area made by
previous
version was ok, no? It really seems like this just does a brute force of
everything
to long (while taking labs() twice) unnecessarily.
> diff --git a/tools/testing/selftests/resctrl/mba_test.c
> b/tools/testing/selftests/resctrl/mba_test.c
> index 7946e32e85c8..707b07687249 100644
> --- a/tools/testing/selftests/resctrl/mba_test.c
> +++ b/tools/testing/selftests/resctrl/mba_test.c
> @@ -60,8 +60,8 @@ static bool show_mba_info(unsigned long *bw_imc, unsigned
> long *bw_resc)
> /* Memory bandwidth from 100% down to 10% */
> for (allocation = 0; allocation < ALLOCATION_MAX / ALLOCATION_STEP;
> allocation++) {
> - unsigned long avg_bw_imc, avg_bw_resc;
> - unsigned long sum_bw_imc = 0, sum_bw_resc = 0;
> + long avg_bw_imc, avg_bw_resc;
> + long sum_bw_imc = 0, sum_bw_resc = 0;
> int avg_diff_per;
> float avg_diff;
>
On second look it only seems necessary to change avg_bw_imc and avg_bw_resc.
What do you think?
> diff --git a/tools/testing/selftests/resctrl/mbm_test.c
> b/tools/testing/selftests/resctrl/mbm_test.c
> index d67ffa3ec63a..30af15020731 100644
> --- a/tools/testing/selftests/resctrl/mbm_test.c
> +++ b/tools/testing/selftests/resctrl/mbm_test.c
> @@ -17,8 +17,8 @@
> static int
> show_bw_info(unsigned long *bw_imc, unsigned long *bw_resc, size_t span)
> {
> - unsigned long avg_bw_imc = 0, avg_bw_resc = 0;
> - unsigned long sum_bw_imc = 0, sum_bw_resc = 0;
> + long avg_bw_imc = 0, avg_bw_resc = 0;
> + long sum_bw_imc = 0, sum_bw_resc = 0;
> int runs, ret, avg_diff_per;
> float avg_diff = 0;
>
Same here wrt the avg_ variables.
>
> base-commit: ddb4c3f25b7b95df3d6932db0b379d768a6ebdf7
> prerequisite-patch-id: b901ece2a5b78503e2fb5480f20e304d36a0ea27
> prerequisite-patch-id: 8d96c4b8c3ed6d9ea2588ef7f594ae0f9f83c279
Reinette
