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

[Aaron Conole <aconole@redhat.com>]

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.

>>>> 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.