What does scheduler/aux mean in msacc?

[Fernando Benavides]

Yeah… the curious thing is that both machines are the same kind of AWS
virtual machines… And I had 2 running OTP22 and 2 running OTP21… and both
OTP22 machines showed xen_hypercall_event_channel_op while both OTP21
didn't (actually… they did, but with a very smaller % of overhead). And,
BTW, the same happened with smp_call_function_many (more overhead
associated with that function in OTP22 than OTP21).

I'll keep digging, but if anybody has any idea of what to look for, I would
appreciate it a lot.

Thanks

On Mon, Jul 6, 2020 at 5:05 PM Max Lapshin <max.lapshin@REDACTED> wrote:

> First post from the internet about xen_hypercall_event_channel_op:
> https://www.scylladb.com/2018/06/21/impact-virtualization-database/
>
> TL;DR: metal server better than virtual
>
> On Mon, Jul 6, 2020 at 5:26 PM Fernando Benavides <elbrujohalcon@REDACTED>
> wrote:
>
>> I'll add another data point…
>> As Lukas suggested, I used *perf* on the running systems and this is
>> what I've got…
>>
>> For OTP22:
>>      2.33%  8_scheduler      beam.smp             [.] process_main
>>
>> *     …the rest of the schedulers running process_main…*     1.57%
>>  6_scheduler      beam.smp             [.] process_main
>>      0.34%  6_scheduler      [kernel.kallsyms]    [k]
>> xen_hypercall_event_channel_op
>>      0.32%  7_scheduler      [kernel.kallsyms]    [k]
>> xen_hypercall_event_channel_op
>>      0.25%  14_scheduler     beam.smp             [.] copy_struct_x
>>      0.25%  2_scheduler      beam.smp             [.] copy_struct_x
>>      0.25%  9_scheduler      [kernel.kallsyms]    [k]
>> xen_hypercall_event_channel_op
>>      0.23%  11_scheduler     [kernel.kallsyms]    [k]
>> xen_hypercall_event_channel_op
>>      0.22%  11_scheduler     beam.smp             [.] copy_shallow_x
>>      0.22%  9_scheduler      libc-2.17.so         [.] __memcpy_ssse3_back
>>      0.20%  13_scheduler     [kernel.kallsyms]    [k] __lock_text_start
>>      0.20%  3_scheduler      [kernel.kallsyms]    [k]
>> xen_hypercall_event_channel_op
>>      0.19%  10_scheduler     beam.smp             [.] erts_cmp_compound
>>
>> For OTP21:
>>      2.45%  4_scheduler      beam.smp             [.] process_main
>>
>> *     …the rest of the schedulers running process_main…*     1.91%
>>  5_scheduler      beam.smp             [.] process_main
>>      0.45%  15_scheduler     [kernel.kallsyms]    [k] __lock_text_start
>>      0.27%  10_scheduler     [kernel.kallsyms]    [k] __lock_text_start
>>      0.27%  3_scheduler      [kernel.kallsyms]    [k] __lock_text_start
>>      0.27%  7_scheduler      [kernel.kallsyms]    [k] __lock_text_start
>>      0.25%  1_scheduler      beam.smp             [.] copy_struct_x
>>      0.25%  2_scheduler      [kernel.kallsyms]    [k] __lock_text_start
>>      0.23%  2_scheduler      beam.smp             [.] copy_struct_x
>>      0.23%  7_scheduler      beam.smp             [.] copy_struct_x
>>      0.20%  4_scheduler      beam.smp             [.] copy_struct_x
>>      0.20%  6_scheduler      [kernel.kallsyms]    [k] __lock_text_start
>>      0.18%  14_scheduler     beam.smp             [.] copy_struct_x
>>
>> I'm not sure what any of those functions are, or why
>> xen_hypercall_event_channel_op is so much popular in OTP22, tho… ��
>>
>> On Mon, Jul 6, 2020 at 3:42 PM Max Lapshin <max.lapshin@REDACTED> wrote:
>>
>>> In a nutshell there is a non-reproducible fluctuation of measurement:
>>> one subsystem takes 10% instead 8%, another 21% instead 23%.
>>>
>>> Totally there seems to be no change.
>>>
>>> It is extremely hard to make reliable measurement that helps to find 8%
>>> to 10% change.
>>>
>>
>>
>> --
>>
>> <https://about.me/elbrujohalcon?promo=email_sig&utm_source=product&utm_medium=email_sig&utm_campaign=gmail_api&utm_content=thumb>
>> Brujo Benavides
>> about.me/elbrujohalcon
>> <https://about.me/elbrujohalcon?promo=email_sig&utm_source=product&utm_medium=email_sig&utm_campaign=gmail_api&utm_content=thumb>
>>
>

-- 
<https://about.me/elbrujohalcon?promo=email_sig&utm_source=product&utm_medium=email_sig&utm_campaign=gmail_api&utm_content=thumb>
Brujo Benavides
about.me/elbrujohalcon
<https://about.me/elbrujohalcon?promo=email_sig&utm_source=product&utm_medium=email_sig&utm_campaign=gmail_api&utm_content=thumb>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://erlang.org/pipermail/erlang-questions/attachments/20200706/2a292278/attachment.htm>