Re: [PATCH v4 4/5] perf stat: Enable iostat mode for x86 platforms

[Alexander Antonov <alexander.antonov@linux.intel.com>]

On 3/9/2021 10:51 AM, liuqi (BA) wrote:
> Hi Alexander,
>
> On 2021/2/3 21:58, Alexander Antonov wrote:
>> This functionality is based on recently introduced sysfs attributes
>> for Intel® Xeon® Scalable processor family (code name Skylake-SP):
>> Commit bb42b3d39781 ("perf/x86/intel/uncore: Expose an Uncore unit to
>> IIO PMON mapping")
>>
>> Mode is intended to provide four I/O performance metrics in MB per each
>> PCIe root port:
>>   - Inbound Read: I/O devices below root port read from the host memory
>>   - Inbound Write: I/O devices below root port write to the host memory
>>   - Outbound Read: CPU reads from I/O devices below root port
>>   - Outbound Write: CPU writes to I/O devices below root port
>>
>> Each metric requiries only one uncore event which increments at every 4B
>> transfer in corresponding direction. The formulas to compute metrics
>> are generic:
>>      #EventCount * 4B / (1024 * 1024)
>>
>> Signed-off-by: Alexander Antonov<alexander.antonov@linux.intel.com>
>> ---
>>   tools/perf/Documentation/perf-iostat.txt |  88 ++++++
>>   tools/perf/Makefile.perf                 |   5 +-
>>   tools/perf/arch/x86/util/Build           |   1 +
>>   tools/perf/arch/x86/util/iostat.c        | 345 +++++++++++++++++++++++
>>   tools/perf/command-list.txt              |   1 +
>>   tools/perf/perf-iostat.sh                |  12 +
>>   6 files changed, 451 insertions(+), 1 deletion(-)
>>   create mode 100644 tools/perf/Documentation/perf-iostat.txt
>>   create mode 100644 tools/perf/perf-iostat.sh
>>
>> diff --git a/tools/perf/Documentation/perf-iostat.txt 
>> b/tools/perf/Documentation/perf-iostat.txt
>> new file mode 100644
>> index 000000000000..165176944031
>> --- /dev/null
>> +++ b/tools/perf/Documentation/perf-iostat.txt
>> @@ -0,0 +1,88 @@
>> +perf-iostat(1)
>> +===============
>> +
>> +NAME
>> +----
>> +perf-iostat - Show I/O performance metrics
>> +
>> +SYNOPSIS
>> +--------
>> +[verse]
>> +'perf iostat' list
>> +'perf iostat' <ports> -- <command> [<options>]
>> +
>> +DESCRIPTION
>> +-----------
>> +Mode is intended to provide four I/O performance metrics per each 
>> PCIe root port:
>> +
>> +- Inbound Read   - I/O devices below root port read from the host 
>> memory, in MB
>> +
>> +- Inbound Write  - I/O devices below root port write to the host 
>> memory, in MB
>> +
>> +- Outbound Read  - CPU reads from I/O devices below root port, in MB
>> +
>> +- Outbound Write - CPU writes to I/O devices below root port, in MB
>> +
>> +OPTIONS
>> +-------
>> +<command>...::
>> +    Any command you can specify in a shell.
>> +
>> +list::
>> +    List all PCIe root ports.
>
> I noticed that "iostat" commond and cmd_iostat() callback function is 
> not registered in cmd_struct in perf.c. So I think "perf iostat list" 
> perhaps can not work properly.
>
> I also test this patchset on x86 platform, and here is the log:
>
> root@ubuntu:/home/lq# ./perf iostat list
> perf: 'iostat' is not a perf-command. See 'perf --help'.
> root@ubuntu:/home/lq# ./perf stat --iostat
> ^C
>  Performance counter stats for 'system wide':
>
>    port             Inbound Read(MB)    Inbound Write(MB) Outbound 
> Read(MB)   Outbound Write(MB)
> 0000:00                    0 0                    0                  0
> 0000:80                    0 0                    0                  0
> 0000:17                    0 0                    0                  0
> 0000:85                    0 0                    0                  0
> 0000:3a                    0 0                    0                  0
> 0000:ae                    0 0                    0                  0
> 0000:5d                    0 0                    0                  0
> 0000:d7                    0 0                    0                  0
>
>        0.611303832 seconds time elapsed
>
>
> root@ubuntu:/home/lq# ./perf stat --iostat=0000:17
> ^C
>  Performance counter stats for 'system wide':
>
>    port             Inbound Read(MB)    Inbound Write(MB) Outbound 
> Read(MB)   Outbound Write(MB)
> 0000:17                    0 0                    0                  0
>
>        0.521317572 seconds time elapsed
>
> So how does following perf iostat list work, did I miss something?
>
> Thanks,
> Qi
>
Hello,

The 'iostat' mode uses aliases mechanism in perf same as 'perf archive' and
in this case you don't need to add function callback into cmd_struct.
For example, the command 'perf iostat list' will be converted to
'perf stat --iostat=list'.

After building the perf tool you should have two shell scripts in tools/perf
directory and one of them is executable, for example:
# make -C tools/perf
# ls -l tools/perf/perf-iostat*
-rwxr-xr-x 1 root root 290 Mar 10 18:17 perf-iostat
-rw-r--r-- 1 root root 290 Feb  3 15:14 perf-iostat.sh

It should be possible to run 'perf iostat' from build directory:
# cd tools/perf
# ./perf iostat list
S0-uncore_iio_0<0000:00>
S1-uncore_iio_0<0000:80>
S0-uncore_iio_1<0000:17>
S1-uncore_iio_1<0000:85>
S0-uncore_iio_2<0000:3a>
S1-uncore_iio_2<0000:ae>
S0-uncore_iio_3<0000:5d>
S1-uncore_iio_3<0000:d7>

Also you can copy 'perf-iostat' to ~/libexec/perf-core/ or just run 
'make install'

# make install
# cp perf /usr/bin/
# ls -lh ~/libexec/perf-core/
total 24K
-rwxr-xr-x 1 root root 1.4K Mar 10 18:17 perf-archive
-rwxr-xr-x 1 root root  290 Mar 10 18:17 perf-iostat
-rwxr-xr-x 1 root root 6.3K Mar 10 18:17 perf-with-kcore
drwxr-xr-x 4 root root 4.0K Nov  5  2019 scripts
drwxr-xr-x 4 root root 4.0K Mar 10 18:17 tests
# perf iostat 0000:17 -I 1000 --interval-count 2
#           time    port             Inbound Read(MB)    Inbound 
Write(MB)    Outbound Read(MB)   Outbound Write(MB)
      1.000220341 0000:17                    0 0                    
0                    0
      2.000569569 0000:17                    0 0                    
0                    0

Actually, Arnaldo has explained before how does aliases mechanism work.

I hope it will solve your issue. Otherwise, please email.

Thank you,
Alexander
>> +
>> +<ports>::
>> +    Select the root ports for monitoring. Comma-separated list is 
>> supported.
>> +
>> +EXAMPLES
>> +--------
>> +
>> +1. List all PCIe root ports (example for 2-S platform):
>> +
>> +   $ perf iostat list
>> +   S0-uncore_iio_0<0000:00>
>> +   S1-uncore_iio_0<0000:80>
>> +   S0-uncore_iio_1<0000:17>
>> +   S1-uncore_iio_1<0000:85>
>> +   S0-uncore_iio_2<0000:3a>
>> +   S1-uncore_iio_2<0000:ae>
>> +   S0-uncore_iio_3<0000:5d>
>> +   S1-uncore_iio_3<0000:d7>
>