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SubjectRe: [PATCH] tools/perf: Fix perf test 7 Simple expression parser on s390
On Wed, Nov 24, 2021 at 1:04 AM Thomas Richter <tmricht@linux.ibm.com> wrote:
>
> Commit fdf1e29b6118 ("perf expr: Add metric literals for topology.")
> fails on s390:
> # ./perf test -Fv 7
> ...
> # FAILED tests/expr.c:173 #num_dies >= #num_packages
> ---- end ----
> Simple expression parser: FAILED!
> #
>
> Investigating this issue leads to these functions:
> build_cpu_topology()
> +--> has_die_topology(void)
> {
> struct utsname uts;
>
> if (uname(&uts) < 0)
> return false;
> if (strncmp(uts.machine, "x86_64", 6))
> return false;
> ....
> }
>
> which always returns false on s390. The caller build_cpu_topology()
> checks has_die_topology() return value. On false the
> the struct cpu_topology::die_cpu_list is not contructed and has zero
> entries. This leads to the failing comparison: #num_dies >= #num_packages.
> s390 of course has a positive number of packages.
>
> Fix this by adding s390 architecture to support CPU die list.
>
> Output after:
> # ./perf test -Fv 7
> 7: Simple expression parser :
> --- start ---
> division by zero
> syntax error
> ---- end ----
> Simple expression parser: Ok
> #
> Cc: Ian Rogers <irogers@google.com>
> Fixes: fdf1e29b6118 ("perf expr: Add metric literals for topology.")
>
> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks!
Ian

> ---
> tools/perf/util/cputopo.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/cputopo.c b/tools/perf/util/cputopo.c
> index 51b429c86f98..aad7a9e6e31b 100644
> --- a/tools/perf/util/cputopo.c
> +++ b/tools/perf/util/cputopo.c
> @@ -165,7 +165,8 @@ static bool has_die_topology(void)
> if (uname(&uts) < 0)
> return false;
>
> - if (strncmp(uts.machine, "x86_64", 6))
> + if (strncmp(uts.machine, "x86_64", 6) &&
> + strncmp(uts.machine, "s390x", 5))
> return false;
>
> scnprintf(filename, MAXPATHLEN, DIE_CPUS_FMT,
> --
> 2.31.1
>

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