[PATCH 15/17] perf tests task_analyzer: fix bad substitution ${$1}

[Aditya Gupta]

Hello Namhyung,

On 21/06/23 20:53, Namhyung Kim wrote:
> Hello Aditya,
>
> On Wed, Jun 21, 2023 at 3:05 AM Aditya Gupta <adityag at linux.ibm.com> wrote:
>> Hello Namhyung,
>>
>> On 21/06/23 06:18, Namhyung Kim wrote:
>>> ...
>>>
>>> $ sudo ./perf test -v task
>>> 114: perf script task-analyzer tests                                 :
>>> --- start ---
>>> test child forked, pid 1771042
>>> Please specify a valid report script(see 'perf script -l' for listing)
>>> FAIL: "invocation of perf command failed" Error message: ""
>>> FAIL: "test_basic" Error message: "Failed to find required string:'Comm'."
>>> Please specify a valid report script(see 'perf script -l' for listing)
>>> FAIL: "invocation of perf command failed" Error message: ""
>>> FAIL: "test_ns_rename" Error message: "Failed to find required string:'Comm'."
>>> ...
>>> test child finished with -1
>>> ---- end ----
>>> perf script task-analyzer tests: FAILED!
>> Can you please check if your environment has libtraceevent devel
>> libraries (or did you compile with `make NO_LIBTRACEEVENT=1`) ? When
>> libtraceevent support is not there, perf record fails and so perf.data
>> doesn't contain the strings it's searching for and hence those errors
>>
>> The error you mentioned has been mentioned and fixed in patch 17/17 of
>> this series.
> Thanks for your reply but It has libtraceevent.  Also, shouldn't it
> skip if it's not?
>
> Thanks,
> Namhyung

The skipping is handled in the 17th patch in this series, and 
considering that patch has also been applied, it will skip the tests if 
perf wasn't built with proper libtraceevent support.

Back to the error, Sorry but I tested again on my system and am unable to reproduce the issue you are seeing when built with libtraceevent support.

This is what I did:

0. git clone --depth=1 https://github.com/torvalds/linux
0. cd linux/tools/perf
0. git am patch_15/17.patch

> I applied ONLY this patch (15/17) of this series, to a fresh linux tree

1. dnf install libtraceevent-devel
2. make clean && make
3. sudo ./perf test -v "perf script task-analyzer tests"       # Working fine, tests passed

4. dnf remove libtraceevent-devel
5. make clean && make                                          # There will also be a warning during build: "libtraceevent is missing limiting functionality"
6. sudo ./perf test -v "perf script task-analyzer tests"       # Fails with the error you posted, which was the case till now, it's skipped when the 17th patch is also applied and perf built without libtraceevent support

The error in the second case (without proper libtraceevent support) is expected, as it was the case till now, that is fixed by the 17th patch, try applying that also and build perf with `make NO_LIBTRACEEVENT=1`, it will skip then.

Can you guide me with the steps to reproduce the error ?

Sidenote: Just in case, please ensure you are running the perf as root here as `perf record -e sched:sched_switch -a -- sleep 1` requires root, which has been used in `prepare_perf_data`

Thanks,
- Aditya