Re: [dpdk-dev] [PATCH V2] app/testpmd: support Tx mbuf free on demand cmd

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 3/9/2021 2:00 PM, Aaron Conole wrote:
> Ferruh Yigit <ferruh.yigit@intel.com> writes:
> 
>> On 3/9/2021 8:49 AM, oulijun wrote:
>>>
>>>
>>> 在 2021/3/9 1:33, Ferruh Yigit 写道:
>>>> On 3/5/2021 9:57 AM, Lijun Ou wrote:
>>>>> From: Chengwen Feng <fengchengwen@huawei.com>
>>>>>
>>>>> This patch support tx_done_cleanup command:
>>>>> tx_done_cleanup port (port_id) (queue_id) (free_cnt)
>>>>>
>>>>> Users must make sure there are no concurrent access to the same Tx
>>>>> queue (like rte_eth_tx_burst, rte_eth_dev_tx_queue_stop and so on)
>>>>> this command executed.
>>>>>
>>>>
>>>> Hi Lijun,
>>>>
>>>> Is the intention to test the PMD implementation?
>>> Yes
>>>> As you highlighted the API is for the datapath, a command for it is
>>>> not easy to use, not sure how useful it will be.
>>>> Perhaps it can be option to use this API in a forwarding engine,
>>>> like 'txonly', controlled by a command, but again not sure what to
>>>> observe/measure etc..
>>>>
>>> We want to do this. But it is diffcult to control the number of sent
>>> packets when used together with other txonly.
>>
>> Agree hard to verify that the implementation this way.
>>
>> What do you think adding an unit test for it,
>> 'app/test/test_ethdev_xx', that can send some packets get the free
>> mbufs number, call the 'rte_eth_tx_done_cleanup()' and check the free
>> mbuf numbers again and return a fail/success accordingly.
>>
>> And this can be a good start for our long missing ethdev unit tests,
>> cc'ed Aaron and Honnappa for the unit test perspective.
> 
> Definitely, let's do it.  There's a start to a guide detailing how to
> create unit tests and suites ;).  I'll post the latest version this week.
> 
>> And if we go with unit test, I think we need to find a way to mark the
>> unit tests that requires HW (this case) for the automation usecases.
> 
> Does it really need HW, though?  Can we use a software device for it?
> Maybe it's a good time to use the null dev for test purposes for these
> libraries.  After all, we want to be testing the library.
> 

For some cases we can use virtual devices, but for this case the actual 
intention is to test the PMD implementation.

Overall I guess we need both, the HW dependent and independent unit tests.

>>>>> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
>>>>> Signed-off-by: Lijun Ou <oulijun@huawei.com>
>>>>> ---
>>>>> V1->V2:
>>>>> - use Tx instead of TX
>>>>> - add note in doc
>>>>> ---
>>>>>    app/test-pmd/cmdline.c                      | 91 +++++++++++++++++++++++++++++
>>>>>    doc/guides/rel_notes/release_21_05.rst      |  2 +
>>>>>    doc/guides/testpmd_app_ug/testpmd_funcs.rst | 11 ++++
>>>>>    3 files changed, 104 insertions(+)
>>>>>
>>>>> diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c
>>>>> index 14110eb..4df0c32 100644
>>>>> --- a/app/test-pmd/cmdline.c
>>>>> +++ b/app/test-pmd/cmdline.c
>>>>> @@ -36,6 +36,7 @@
>>>>>    #include <rte_pci.h>
>>>>>    #include <rte_ether.h>
>>>>>    #include <rte_ethdev.h>
>>>>> +#include <rte_ethdev_driver.h>
>>>>
>>>> This header for PMDs to include, applications shouldn't include
>>>> this, including this means you are accessing dpdk internals which
>>>> you shouldn't access.
>>>>
>>> Thanks. I will fix it.
>>>>>    #include <rte_string_fns.h>
>>>>>    #include <rte_devargs.h>
>>>>>    #include <rte_flow.h>
>>>>> @@ -675,6 +676,9 @@ static void cmd_help_long_parsed(void *parsed_result,
>>>>>                "set port (port_id) ptype_mask (ptype_mask)\n"
>>>>>                "    set packet types classification for a specific port\n\n"
>>>>> +            "tx_done_cleanup (port_id) (queue_id) (free_cnt)\n"
>>>>> +            "    Cleanup a Tx queue's mbuf on a port\n\n"
>>>>> +
>>>>>                "set port (port_id) queue-region region_id (value) "
>>>>>                "queue_start_index (value) queue_num (value)\n"
>>>>>                "    Set a queue region on a port\n\n"
>>>>> @@ -16910,6 +16914,92 @@ cmdline_parse_inst_t cmd_showport_macs = {
>>>>>        },
>>>>>    };
>>>>> +/* *** tx_done_cleanup *** */
>>>>> +struct cmd_tx_done_cleanup_result {
>>>>> +    cmdline_fixed_string_t clean;
>>>>> +    cmdline_fixed_string_t port;
>>>>> +    uint16_t port_id;
>>>>> +    uint16_t queue_id;
>>>>> +    uint32_t free_cnt;
>>>>> +};
>>>>> +
>>>>> +static void
>>>>> +cmd_tx_done_cleanup_parsed(void *parsed_result,
>>>>> +               __rte_unused struct cmdline *cl,
>>>>> +               __rte_unused void *data)
>>>>> +{
>>>>> +    struct cmd_tx_done_cleanup_result *res = parsed_result;
>>>>> +    struct rte_eth_dev *dev;
>>>>> +    uint16_t port_id = res->port_id;
>>>>> +    uint16_t queue_id = res->queue_id;
>>>>> +    uint32_t free_cnt = res->free_cnt;
>>>>> +    int ret;
>>>>> +
>>>>> +    if (!rte_eth_dev_is_valid_port(port_id)) {
>>>>> +        printf("Invalid port_id %u\n", port_id);
>>>>> +        return;
>>>>> +    }
>>>>> +
>>>>> +    dev = &rte_eth_devices[port_id];
>>>>
>>>> Similar to above comment 'rte_eth_devices' is the internal
>>>> variable, applications should not access it directly.
>>>>
>>> No API is available, and multiple references exist in the testpmd file.
>>
>> Technically 'rte_eth_devices' is still visible to the applications
>> because of the static inline functions, in theory it should be hidden.
>>
>> But this variable accessed by our test application multiple times may
>> be the sign that something more is missing.
>>
>> Thomas, Andrew, what to you think to try to clean this usage from
>> testpmd and add more APIs if needed for this?
>>
>>>>> +    if (queue_id >= dev->data->nb_tx_queues) {
>>>>> +        printf("Invalid Tx queue_id %u\n", queue_id);
>>>>> +        return;
>>>>> +    }
>>>>> +
>>>>
>>>> Number of the queues can be get via 'rte_eth_dev_info_get()'.
>>>>
>>> This is also called in txonly. Do you want to replace it?
>>
>> That would be good if you can do it in a separate patch, thank you.
>