Software Tuning, Performance Optimization & Platform Monitoring
Discussion around monitoring and software tuning methodologies, Performance Monitoring Unit (PMU) of Intel microprocessors, and platform monitoring

what does "skip" mean in the context of perf test

gostanian__richard
New Contributor I
443 Views

perf test

reports on the availability of various functionalities supported by perf in the current environment. 

On one of my machines, I get output that looks like

g32 > perf test
 1: vmlinux symtab matches kallsyms                       : Skip
 2: Detect openat syscall event                           : FAILED!
 3: Detect openat syscall event on all cpus               : FAILED!
 4: Read samples using the mmap interface                 : FAILED!
 5: Test data source output                               : Ok
 6: Parse event definition strings                        : FAILED!
 7: Simple expression parser                              : Ok
 8: PERF_RECORD_* events & perf_sample fields             : Ok
 9: Parse perf pmu format                                 : Ok
10: DSO data read                                         : Ok
11: DSO data cache                                        : Ok
12: DSO data reopen                                       : Ok
13: Roundtrip evsel->name                                 : Ok
14: Parse sched tracepoints fields                        : FAILED!
15: syscalls:sys_enter_openat event fields                : FAILED!
16: Setup struct perf_event_attr                          : Ok
17: Match and link multiple hists                         : Ok
18: 'import perf' in python                               : Ok
19: Breakpoint overflow signal handler                    : Ok
20: Breakpoint overflow sampling                          : Ok
21: Number of exit events of a simple workload            : Skip
22: Software clock events period values                   : Ok

The meaning of "OK" and "FAILED" is clear, but what does "Skip" mean?

0 Kudos
1 Reply
HadiBrais
New Contributor III
443 Views

You can repeat the particular test that was skipped with the verbose option as follows:

perf test -v 1

Here, I've specified the test number 1, which corresponds to the test "vmlinux symtab matches kallsyms." The verbose option can be helpful in understanding the result of a test. If you omit the test number, all tests will be attempted in verbose mode.

Consider test 1 as an example. It may output the following:

Couldn't find a vmlinux that matches the kernel running on this machine, skipping test

The solution is clear now; vmlinux that matches the kernel has to be installed in order to perform the test.

Tests may also be skipped explicitly using the -s command-line option.

Reply