> On May 18, 2020, at 4:47 AM, Ferruh Yigit <ferruh.yi...@intel.com> wrote: > > On 5/15/2020 9:33 PM, Dharmik Thakkar wrote: >> Hi Ferruh, >> >>> On May 15, 2020, at 7:15 AM, Ferruh Yigit <ferruh.yi...@intel.com> wrote: >>> >>> On 5/8/2020 11:38 PM, Dharmik Thakkar wrote: >>>> Update documentation for 'show fwd' testpmd runtime function to show >>>> CPU cycles/packet example. >>>> >>>> Signed-off-by: Dharmik Thakkar <dharmik.thak...@arm.com> >>>> Reviewed-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> >>>> Reviewed-by: Phil Yang <phil.y...@arm.com> >>>> --- >>>> v2: >>>> - Use shorter lines, up to 100. >>>> --- >>>> doc/guides/testpmd_app_ug/testpmd_funcs.rst | 53 +++++++++++++-------- >>>> 1 file changed, 33 insertions(+), 20 deletions(-) >>>> >>>> diff --git a/doc/guides/testpmd_app_ug/testpmd_funcs.rst >>>> b/doc/guides/testpmd_app_ug/testpmd_funcs.rst >>>> index a360ecccfd3f..441ed41e3803 100644 >>>> --- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst >>>> +++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst >>>> @@ -351,26 +351,39 @@ Example for the io forwarding engine, with some >>>> packet drops on the tx side:: >>>> >>>> testpmd> show fwd stats all >>>> >>>> - ------- Forward Stats for RX Port= 0/Queue= 0 -> TX Port= 1/Queue= 0 >>>> ------- >>>> - RX-packets: 274293770 TX-packets: 274293642 TX-dropped: 128 >>>> - >>>> - ------- Forward Stats for RX Port= 1/Queue= 0 -> TX Port= 0/Queue= 0 >>>> ------- >>>> - RX-packets: 274301850 TX-packets: 274301850 TX-dropped: 0 >>>> - >>>> - ---------------------- Forward statistics for port 0 >>>> ---------------------- >>>> - RX-packets: 274293802 RX-dropped: 0 RX-total: >>>> 274293802 >>>> - TX-packets: 274301862 TX-dropped: 0 TX-total: >>>> 274301862 >>>> - >>>> ---------------------------------------------------------------------------- >>>> - >>>> - ---------------------- Forward statistics for port 1 >>>> ---------------------- >>>> - RX-packets: 274301894 RX-dropped: 0 RX-total: >>>> 274301894 >>>> - TX-packets: 274293706 TX-dropped: 128 TX-total: >>>> 274293834 >>>> - >>>> ---------------------------------------------------------------------------- >>>> - >>>> - +++++++++++++++ Accumulated forward statistics for all >>>> ports+++++++++++++++ >>>> - RX-packets: 548595696 RX-dropped: 0 RX-total: >>>> 548595696 >>>> - TX-packets: 548595568 TX-dropped: 128 TX-total: >>>> 548595696 >>>> - >>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >>>> + ------- Forward Stats for RX Port= 0/Queue= 0 -> TX Port= 1/Queue= 0 >>>> ------- >>>> + RX-packets: 43536504 TX-packets: 43536488 TX-dropped: 0 >>>> + >>>> + ------- Forward Stats for RX Port= 1/Queue= 0 -> TX Port= 0/Queue= 0 >>>> ------- >>>> + RX-packets: 149738504 TX-packets: 149738504 TX-dropped: 0 >>>> + >>>> + ------- Forward Stats for RX Port= 1/Queue= 1 -> TX Port= 0/Queue= 1 >>>> ------- >>>> + RX-packets: 149753052 TX-packets: 149753052 TX-dropped: 0 >>>> + >>>> + ---------------------- Forward statistics for port 0 >>>> ---------------------- >>>> + RX-packets: 43538881 RX-dropped: 72 RX-total: >>>> 43538953 >>>> + TX-packets: 299491753 TX-dropped: 0 TX-total: >>>> 299491753 >>>> + >>>> ---------------------------------------------------------------------------- >>>> + >>>> + ---------------------- Forward statistics for port 1 >>>> ---------------------- >>>> + RX-packets: 299493085 RX-dropped: 8357 RX-total: >>>> 299501442 >>>> + TX-packets: 43539683 TX-dropped: 0 TX-total: >>>> 43539683 >>>> + >>>> ---------------------------------------------------------------------------- >>>> + >>>> + +++++++++++++++ Accumulated forward statistics for all >>>> ports+++++++++++++++ >>>> + RX-packets: 343031966 RX-dropped: 8429 RX-total: >>>> 343040395 >>>> + TX-packets: 343031436 TX-dropped: 0 TX-total: >>>> 343031436 >>>> + >>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >>>> + >>>> + CPU cycles/packet=14.28 (total cycles=4899533541 / total RX >>>> packets=343031966) at 200 MHz Clock >>> >>> Hi Dharmik, >>> >>> Overall it is OK to show "CPU cycles/packet", but my concern is numbers can >>> be >>> misleading, because for example the numbers I am getting is like below: >>> >>> CPU cycles/packet=4.38 (total cycles=32871036274 / total RX >>> packets=7511734336) >>> at 2100 MHz Clock >> >> CPU cycles/packet shown above is a part of the example. The numbers are as >> per the statistics shown in the example. > > I know but now you are showing a performance number and it is specific to a > platform, my concern it may be misleading and create false expectations for > others.
Ok, makes sense. > >> >>> >>>> + >>>> +.. note:: >>>> + >>>> + Measuring CPU cycles/packet requires enabling >>>> CONFIG_RTE_TEST_PMD_RECORD_CORE_TX_CYCLES >>> >>> s/TX_CYCLES/CYCLES >> >> Sorry, didn’t understand this comment. > > There is no 'CONFIG_RTE_TEST_PMD_RECORD_CORE_TX_CYCLES' config option. Got it, will update. > >> >>> >>>> + configuration option. On aarch64 platforms, by default, the cycles are >>>> counted using >>>> + generic counter which runs at a lower frequency than the CPU clock. To >>>> get the cycles/packet >>>> + at CPU clock frequency, please scale the cycles/packet to CPU clock >>>> frequency. >>>> + Alternatively, use the PMU based cycle counter. >>> >>> Not sure the "aarch64 platforms" note suits to here, where documents the >>> command. And I can see the platform documentation already updated for this. >> >> This additional comment about aarch64 platforms is to provide complete >> information to the users with regards to the config option >> and offer a better understanding of the CPU cycles/packet numbers. IMO, >> without this note, CPU cycles/packet numbers can be misleading. > > This is testpmd documentation to describe "show fwd stats" command. We are > adding a note to say with a config option it may also show performance data, > which is OK. But starting to describe the platform differences for this config > option looks to much details for the scope of the document. For testpmd I > would > prefer command usage independent from platforms, otherwise the documentation > may > become too confusing/complex. > But agree to provide the information for the specific platform, which you are > already doing in other patch in the platform documentation. Alright, I will remove platform in the next version. > >> >>> >>> Combining above two comments, what do you think instead of replacing >>> existing >>> stats, add a note saying enabling 'CONFIG_RTE_TEST_PMD_RECORD_CORE_CYCLES' >>> appends "CPU cycles/packet" and give above two samples, like: >>> >>> " >>> Enabling RTE_TEST_PMD_RECORD_CORE_CYCLES appends "CPU cycles/packet" stats, >>> like: >>> >>> CPU cycles/packet=4.38 (total cycles=32871036274 / total RX >>> packets=7511734336) >>> at 2100 MHz Clock >>> OR >>> CPU cycles/packet=14.28 (total cycles=4899533541 / total RX >>> packets=343031966) >>> at 200 MHz Clock >>> " >> >> Yes, this is also an option. IMO, numbers shown within CPU cycles/packet >> example should be consistent with the forward statistics numbers. >> > > This part is just the sample of the "CPU cycles/packet" output, I think it > provides enough context to be understandable without matching Rx packet count > in > above part of the stats. Instead of adding 2 samples, do you think using xxx is best? For example: CPU cycles/packet=xx.dd (total cycles=xxxx / total RX packets=xxxx) at xxxx MHz clock
