[dpdk-dev] [PATCH 3/5] doc: add cycles per packet in testpmd user guide
Dharmik Thakkar
Dharmik.Thakkar at arm.com
Fri May 8 00:27:53 CEST 2020
Hi Jerin,
> On May 7, 2020, at 12:24 AM, Jerin Jacob <jerinjacobk at gmail.com> wrote:
>
> On Thu, May 7, 2020 at 3:30 AM Dharmik Thakkar <dharmik.thakkar at arm.com> wrote:
>>
>> Update documentation for 'show fwd' testpmd runtime function to show
>> CPU cycles/packet example.
>>
>> Signed-off-by: Dharmik Thakkar <dharmik.thakkar at arm.com>
>> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli at arm.com>
>> Reviewed-by: Phil Yang <phil.yang at arm.com>
>> ---
>> doc/guides/testpmd_app_ug/testpmd_funcs.rst | 51 +++++++++++++--------
>> 1 file changed, 31 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..2e565ccdbcd4 100644
>> --- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
>> +++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
>> @@ -351,26 +351,37 @@ 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
>> +
>> +.. note::
>> +
>> + Measuring CPU cycles/packet requires enabling CONFIG_RTE_TEST_PMD_RECORD_CORE_TX_CYCLES configuration option.
>
> IMO, it a very useful feature for CI/CD and development as we don't
> need to see any Traffic generator to see any regression.
>
> I think, enabling CONFIG_RTE_TEST_PMD_RECORD_CORE_TX_CYCLES
> configuration is overhead to use in all the environments.
>
> How about adding a "new forward" engine with and remove
> CONFIG_RTE_TEST_PMD_RECORD_CORE_TX_CYCLES.
> The new forward engine will have
> CONFIG_RTE_TEST_PMD_RECORD_CORE_TX_CYCLES code enabled.
> So the application can use the forward engine dynamically. aka the
> same build works for both cases.
Yes, this can be done as a separate patch.
The idea of this patch is to update the documentation with the missing CPU cycles/packet information.
>
>
>> + 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.
>>
>> clear fwd
>> ~~~~~~~~~
>> --
>> 2.20.1
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