[PATCH 1/2] perf record: Support s390 random socket_id assignment

[PATCH 1/2] perf record: Support s390 random socket_id assignment

[Thomas Richter]

On s390 the socket identifier assigned to a CPU identifier is
random and (depending on the configuration of the LPAR) may be higher
than the CPU identifier. This is currently not supported.

Fix this by allowing arbitrary socket identifiers being assigned to
CPU id.

Output before:

[root@p23lp27 perf]# ./perf report --header -I -v
 ...
 socket_id number is too big.You may need to upgrade the perf tool.
 Error:
 The perf.data file has no samples!
 # ========
 # captured on    : Tue May 29 09:29:57 2018
 # header version : 1
 ...
 # Core ID and Socket ID information is not available
 ...
[root@p23lp27 perf]#

Output after:
[root@p23lp27 perf]# ./perf report --header -I -v
 ...
 Error:
 The perf.data file has no samples!
 # ========
 # captured on    : Tue May 29 09:29:57 2018
 # header version : 1
 ...
 # CPU 0: Core ID 0, Socket ID 6
 # CPU 1: Core ID 1, Socket ID 3
 # CPU 2: Core ID -1, Socket ID -1
 ...
[root@p23lp27 perf]#

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
---
 tools/perf/util/header.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index a8bff2178fbc..34e9d6b9d945 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -2113,6 +2113,7 @@ static int process_cpu_topology(struct feat_fd *ff, void *data __maybe_unused)
 	int cpu_nr = ff->ph->env.nr_cpus_avail;
 	u64 size = 0;
 	struct perf_header *ph = ff->ph;
+	bool do_core_id_test = true;
 
 	ph->env.cpu = calloc(cpu_nr, sizeof(*ph->env.cpu));
 	if (!ph->env.cpu)
@@ -2167,6 +2168,13 @@ static int process_cpu_topology(struct feat_fd *ff, void *data __maybe_unused)
 		return 0;
 	}
 
+	/* On s390 the socket_id number is not related to the numbers of cpus.
+	 * The socket_id number might be higher than the numbers of cpus.
+	 * This depends on the configuration.
+	 */
+	if (ph->env.arch && !strncmp(ph->env.arch, "s390", 4))
+		do_core_id_test = false;
+
 	for (i = 0; i < (u32)cpu_nr; i++) {
 		if (do_read_u32(ff, &nr))
 			goto free_cpu;
@@ -2176,7 +2184,7 @@ static int process_cpu_topology(struct feat_fd *ff, void *data __maybe_unused)
 		if (do_read_u32(ff, &nr))
 			goto free_cpu;
 
-		if (nr != (u32)-1 && nr > (u32)cpu_nr) {
+		if (do_core_id_test && nr != (u32)-1 && nr > (u32)cpu_nr) {
 			pr_debug("socket_id number is too big."
 				 "You may need to upgrade the perf tool.\n");
 			goto free_cpu;
-- 
2.14.3

[PATCH 2/2] perf test: Fix test 39 Session topology for s390

[Thomas Richter]

On s390 this test case fails because the socket identifiction numbers
assigned to the CPU are higher than the CPU identification numbers.

Fix this by adding the platform architecture into the perf data header
flag information. This helps identifiing the test platform and handles
s390 specifics in process_cpu_topology().

Output before:
[root@p23lp27 perf]# ./perf test -vvvvv -F 39
39: Session topology                                      :
--- start ---
templ file: /tmp/perf-test-iUv755
socket_id number is too big.You may need to upgrade the perf tool.
---- end ----
Session topology: Skip
[root@p23lp27 perf]#

Output after:
[root@p23lp27 perf]# ./perf test -vvvvv -F 39
39: Session topology                                      :
--- start ---
templ file: /tmp/perf-test-8X8VTs
CPU 0, core 0, socket 6
CPU 1, core 1, socket 3
---- end ----
Session topology: Ok
[root@p23lp27 perf]#

Fixes: c84974ed9fb6 ("perf test: Add entry to test cpu topology")
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
---
 tools/perf/tests/topology.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/perf/tests/topology.c b/tools/perf/tests/topology.c
index 40e30a26b23c..9497d02f69e6 100644
--- a/tools/perf/tests/topology.c
+++ b/tools/perf/tests/topology.c
@@ -45,6 +45,7 @@ static int session_write_header(char *path)
 
 	perf_header__set_feat(&session->header, HEADER_CPU_TOPOLOGY);
 	perf_header__set_feat(&session->header, HEADER_NRCPUS);
+	perf_header__set_feat(&session->header, HEADER_ARCH);
 
 	session->header.data_size += DATA_SIZE;
 
-- 
2.14.3

Re: [PATCH 1/2] perf record: Support s390 random socket_id assignment

[Arnaldo Carvalho de Melo]

Em Mon, Jun 11, 2018 at 09:31:52AM +0200, Thomas Richter escreveu:
> On s390 the socket identifier assigned to a CPU identifier is
> random and (depending on the configuration of the LPAR) may be higher
> than the CPU identifier. This is currently not supported.
> 
> Fix this by allowing arbitrary socket identifiers being assigned to
> CPU id.
> 
> Output before:

Thanks, applied both patches in this series,

- Arnaldo