Re: [PATCH RFC 5/7] perf pmu: Support matching by sysid

John Garry
2020-02-12T10:08:51Z

On 11/02/2020 15:07, John Garry wrote:
> On 11/02/2020 13:47, Jiri Olsa wrote:
>
> Hi Jirka,
>
>>>>> +
>>>>> +    return buf;
>>>>> +}
>>>>> +
>>>
>>> I have another series to add kernel support for a system identifier
>>> sysfs
>>> entry, which I sent after this series:
>>>
>>> https://lore.kernel.org/linux-acpi/1580210059-199540-1-git-send-email-john.garry@huawei.com/
>>>
>>>
>>> It is different to what I am relying on here - it uses a kernel soc
>>> driver
>>> for firmware ACPI PPTT identifier. Progress is somewhat blocked at the
>>> moment however and I may have to use a different method:
>>>
>>> https://lore.kernel.org/linux-acpi/20200128123415.GB36168@bogus/
>>
>> I'll try to check ;-)
>
> Summary is that there exists an ACPI firmware field which we could
> expose to userspace via sysfs - this would provide the system id.
> However there is a proposal to deprecate it in the ACPI standard and, as
> such, would prefer that we don't add kernel support for it at this stage.
>
> So I am evaluating the alternative in the meantime, which again is some
> firmware method which should allow us to expose a system id to userspace
> via sysfs. Unfortunately this is arm specific. However, other archs can
> still provide their own method, maybe a soc driver:
>
> Documentation/ABI/testing/sysfs-devices-soc#n15
>
>>
>>>
>>>>> +static char *perf_pmu__getsysid(void)
>>>>> +{
>>>>> +    char *sysid;
>>>>> +    static bool printed;
>>>>> +
>>>>> +    sysid = getenv("PERF_SYSID");
>>>>> +    if (sysid)
>>>>> +        sysid = strdup(sysid);
>>>>> +
>>>>> +    if (!sysid)
>>>>> +        sysid = get_sysid_str();
>>>>> +    if (!sysid)
>>>>> +        return NULL;
>>>>> +
>>>>> +    if (!printed) {
>>>>> +        pr_debug("Using SYSID %s\n", sysid);
>>>>> +        printed = true;
>>>>> +    }
>>>>> +    return sysid;
>>>>> +}
>>>>
>>>> this part is getting complicated and AFAIK we have no tests for it
>>>>
>>>> if you could think of any tests that'd be great.. Perhaps we could
>>>> load 'our' json test files and check appropriate events/aliasses
>>>> via in pmu object.. or via parse_events interface.. those test aliases
>>>> would have to be part of perf, but we have tests compiled in anyway
>>>
>>> Sorry, I don't fully follow.
>>>
>>> Are you suggesting that we could load the specific JSONs tables for a
>>> system
>>> from the host filesystem?
>>
>> I wish to see some test for all this.. I can only think about having
>> 'test' json files compiled with perf and 'perf test' that looks them
>> up and checks that all is in the proper place
>
> OK, let me consider this part for perf test support.

I will note that perf test has many issues on my arm64 board:

do] password for john:
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 : Skip
17: Match and link multiple hists : Ok
18: 'import perf' in python : Ok
21: Breakpoint accounting : Ok
22: Watchpoint :
22.1: Read Only Watchpoint : Ok
22.2: Write Only Watchpoint : Ok
22.3: Read / Write Watchpoint : Ok
22.4: Modify Watchpoint : Ok
23: Number of exit events of a simple workload : Ok
24: Software clock events period values : Ok
25: Object code reading : Ok
26: Sample parsing : Ok
27: Use a dummy software event to keep tracking : Ok
28: Parse with no sample_id_all bit set : Ok
29: Filter hist entries : Ok
30: Lookup mmap thread : Ok
31: Share thread maps : Ok
32: Sort output of hist entries : Ok
33: Cumulate child hist entries : Ok
34: Track with sched_switch : Ok
35: Filter fds with revents mask in a fdarray : Ok
36: Add fd to a fdarray, making it autogrow : Ok
37: kmod_path__parse : Ok
38: Thread map : Ok
39: LLVM search and compile :
39.1: Basic BPF llvm compile : Skip
39.2: kbuild searching : Skip
39.3: Compile source for BPF prologue generation : Skip
39.4: Compile source for BPF relocation : Skip
40: Session topology : FAILED!
41: BPF filter :
41.1: Basic BPF filtering : Skip
41.2: BPF pinning : Skip
41.3: BPF prologue generation : Skip
41.4: BPF relocation checker : Skip
42: Synthesize thread map : Ok
43: Remove thread map : Ok
44: Synthesize cpu map : Ok
45: Synthesize stat config : Ok
46: Synthesize stat : Ok
47: Synthesize stat round : Ok
48: Synthesize attr update : Ok
49: Event times : Ok
50: Read backward ring buffer : FAILED!
51: Print cpu map : Ok
52: Merge cpu map : Ok
53: Probe SDT events : Ok
54: is_printable_array : Ok
55: Print bitmap : Ok
56: perf hooks umber__scnprintf
: Ok
59: mem2node : Ok
60: time utils : Ok
61: Test jit_write_elf : Ok
62: maps__merge_in : Ok
63: DWARF unwind : Ok
64: Check open filename arg using perf trace + vfs_getname: FAILED!
65: Add vfs_getname probe to get syscall args filenames : FAILED!
66: Use vfs_getname probe to get syscall args filenames : FAILED!
67: Zstd perf.data compression/decompression : Ok
68: probe libc's inet_pton & backtrace it with ping : Skip
john@ubuntu:~/linux$

I know that the perf tool definitely has issues for system topology for
arm64, which I need to check on.

Maybe I can conscribe help internally to help check the rest...

Thanks,
john