lkml.org 
[lkml]   [2017]   [Oct]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 2/2] perf tools: arm-spe: add customized strerror function
Add a routine to try to help the user determine how they're
supposed to use the SPE driver.

Example #1: Trouble setting sample rate:

$ sudo ./perf record -e arm_spe_0/ts_enable=1,pa_enable=1/ -F 1 true
Error:
required sample period missing. Use '--count=<non-zero value>'
$ ./perf record -e arm_spe_0/ts_enable=1/ -c 0 true
Error:
required sample period missing. Use '--count=<non-zero value>'
$ ./perf record -e arm_spe_0/ts_enable=1/ -c 1 true
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.009 MB perf.data ]
$

Example #2: Non-privileged user tries to obtain physical address data:

$ ./perf record -e arm_spe_0/ts_enable=1,pa_enable=1/ -c 1 true
Error:
arm_spe_0/ts_enable=1,pa_enable=1/:u: physical address and time, and EL1 context ID data collection
require admin privileges
$ sudo ./perf record -e arm_spe_0/ts_enable=1,pa_enable=1/ -c 1 true
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.054 MB perf.data ]
$

Example #3: Trying to exclude idle profiling:

$ sudo ./perf record -e arm_spe_0/ts_enable=1,pa_enable=1/I -c 1 true
Error:
arm_spe_0/ts_enable=1,pa_enable=1/I: Cannot exclude profiling when idle, try without //I
$

Signed-off-by: Kim Phillips <kim.phillips@arm.com>
---
DO NOT APPLY: This should really be an RFC, since depends on this RFC:

https://www.spinics.net/lists/arm-kernel/msg613725.html

but providing as part of SPE tool patch anyway in case it helps
resolve the RFC.

tools/perf/arch/arm64/util/evsel.c | 43 ++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)

diff --git a/tools/perf/arch/arm64/util/evsel.c b/tools/perf/arch/arm64/util/evsel.c
index e09cbb5d1518..222bf761d11b 100644
--- a/tools/perf/arch/arm64/util/evsel.c
+++ b/tools/perf/arch/arm64/util/evsel.c
@@ -70,6 +70,44 @@ target__has_task(target), target__has_cpu(target), target__none(target)
return 0;
}

+#ifdef HAVE_AUXTRACE_SUPPORT
+static int strerror_arm_spe(struct perf_evsel *evsel,
+ struct target *target __maybe_unused,
+ int err, char *msg, size_t size)
+{
+ const char *evname = perf_evsel__name(evsel);
+ struct perf_event_attr *attr = &evsel->attr;
+
+ switch (err) {
+ case EOPNOTSUPP:
+ if (attr->exclude_idle)
+ return scnprintf(msg, size,
+ "%s: Cannot exclude profiling when idle, try without //I\n", evname);
+ return scnprintf(msg, size, "%s: unsupported error code:\n"
+ "EITHER this driver may not support a possibly h/w-implementation\n"
+ "\tdefined event filter bit that has been set in the PMSEVFR register\n"
+ "OR h/w doesn't support filtering by one or more of: latency,\n"
+ "\toperation type, or events\n", evname);
+ break;
+ case EACCES:
+ if (strstr(evname, "pa_enable") || strstr(evname, "pct_enable"))
+ return scnprintf(msg, size,
+ "%s: physical address and time, and EL1 context ID data collection\n"
+ "\trequire admin privileges\n", evname);
+ break;
+ case EINVAL:
+ if (attr->freq || !attr->sample_period)
+ return scnprintf(msg, size,
+ "required sample period missing. Use '--count=<non-zero value>'\n");
+ break;
+ default:
+ break;
+ }
+
+ return 0;
+}
+#endif
+
int perf_evsel__open_strerror_arch(struct perf_evsel *evsel,
struct target *target,
int err, char *msg, size_t size)
@@ -80,5 +118,10 @@ int perf_evsel__open_strerror_arch(struct perf_evsel *evsel,
if (strstarts(evname, "ccn"))
return ccn_strerror(evsel, target, err, msg, size);

+#ifdef HAVE_AUXTRACE_SUPPORT
+ if (strstarts(evname, "arm_spe"))
+ return strerror_arm_spe(evsel, target, err, msg, size);
+#endif
+
return 0;
}
--
2.14.2
\
 
 \ /
  Last update: 2017-10-28 20:20    [W:0.031 / U:0.132 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site