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

["Li, Xiaoyun" <xiaoyun.li@intel.com>]

Hi
Sorry, forgot to send this in last patchset.

> -----Original Message-----
> From: Lijun Ou <oulijun@huawei.com>
> Sent: Friday, March 5, 2021 15:33
> To: Yigit, Ferruh <ferruh.yigit@intel.com>
> Cc: Li, Xiaoyun <xiaoyun.li@intel.com>; dev@dpdk.org;
> linuxarm@openeuler.org
> Subject: [PATCH] app/testpmd: support Tx mbuf free on demand cmd
> 
> From: Chengwen Feng <fengchengwen@huawei.com>
> 
> This patch support tx_done_cleanup command:
> tx_done_cleanup port (port_id) (queue_id) (free_cnt)
> 
> User 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) when this command

Users ...... this command is executed.

> executed.
> 
> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
> Signed-off-by: Lijun Ou <oulijun@huawei.com>
> ---
>  app/test-pmd/cmdline.c                      | 91 +++++++++++++++++++++++++++++
>  doc/guides/rel_notes/release_21_05.rst      |  2 +
>  doc/guides/testpmd_app_ug/testpmd_funcs.rst |  7 +++
>  3 files changed, 100 insertions(+)
> 
> diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c index
> 14110eb..832ae70 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>
>  #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];
> +	if (queue_id >= dev->data->nb_tx_queues) {
> +		printf("Invalid TX queue_id %u\n", queue_id);

Tx? You just want to send a patch to use Rx/Tx. You should keep concurrency.

> +		return;
> +	}
> +
> +	if (dev->data->tx_queue_state[queue_id] !=
> +		RTE_ETH_QUEUE_STATE_STARTED) {
> +		printf("TX queue_id %u not started!\n", queue_id);

Tx?

> +		return;
> +	}
> +
> +	/*
> +	 * rte_eth_tx_done_cleanup is a dataplane API, user 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) when this
> API
> +	 * called.
> +	 */

And I have some concerns on this. Users cannot know about this unless they read your code. I don't think this will likely happen.
So you should document this in testpmd doc when you introduced this command.

Or maybe you can have a way to stop that to happen. Maybe checking "test_done && engine != rxonly" before this?
In your comment, the tx forwarding shouldn't happen, right? Every fwd engine except rxonly will contain tx.
Well, it's still a rough way because tx may not happen even if it's io fwd.

Maybe other people have better ideas. Otherwise, you should at least document it.
@Yigit, Ferruh What do you think? Is there a better way?

> +	ret = rte_eth_tx_done_cleanup(port_id, queue_id, free_cnt);
> +	if (ret < 0) {
> +		printf("Failed to cleanup mbuf for port %u TX queue %u "

Tx?

> +		       "error desc: %s(%d)\n",
> +		       port_id, queue_id, strerror(-ret), ret);
> +		return;
> +	}
> +
> +	printf("Cleanup port %u TX queue %u mbuf nums: %u\n",

Tx?

> +	       port_id, queue_id, ret);
> +}
> +
> +cmdline_parse_token_string_t cmd_tx_done_cleanup_clean =
> +	TOKEN_STRING_INITIALIZER(struct cmd_tx_done_cleanup_result, clean,
> +				 "tx_done_cleanup");
> +cmdline_parse_token_string_t cmd_tx_done_cleanup_port =
> +	TOKEN_STRING_INITIALIZER(struct cmd_tx_done_cleanup_result, port,
> +				 "port");
> +cmdline_parse_token_num_t cmd_tx_done_cleanup_port_id =
> +	TOKEN_NUM_INITIALIZER(struct cmd_tx_done_cleanup_result, port_id,
> +			      UINT16);
> +cmdline_parse_token_num_t cmd_tx_done_cleanup_queue_id =
> +	TOKEN_NUM_INITIALIZER(struct cmd_tx_done_cleanup_result,
> queue_id,
> +			      UINT16);
> +cmdline_parse_token_num_t cmd_tx_done_cleanup_free_cnt =
> +	TOKEN_NUM_INITIALIZER(struct cmd_tx_done_cleanup_result,
> free_cnt,
> +			      UINT32);
> +
> +cmdline_parse_inst_t cmd_tx_done_cleanup = {
> +	.f = cmd_tx_done_cleanup_parsed,
> +	.data = NULL,
> +	.help_str = "tx_done_cleanup port <port_id> <queue_id> <free_cnt>",
> +	.tokens = {
> +		(void *)&cmd_tx_done_cleanup_clean,
> +		(void *)&cmd_tx_done_cleanup_port,
> +		(void *)&cmd_tx_done_cleanup_port_id,
> +		(void *)&cmd_tx_done_cleanup_queue_id,
> +		(void *)&cmd_tx_done_cleanup_free_cnt,
> +		NULL,
> +	},
> +};
> +
>  /*
> *****************************************************************
> *************** */
> 
>  /* list of instructions */
> @@ -17035,6 +17125,7 @@ cmdline_parse_ctx_t main_ctx[] = {
>  	(cmdline_parse_inst_t *)&cmd_config_rss_reta,
>  	(cmdline_parse_inst_t *)&cmd_showport_reta,
>  	(cmdline_parse_inst_t *)&cmd_showport_macs,
> +	(cmdline_parse_inst_t *)&cmd_tx_done_cleanup,
>  	(cmdline_parse_inst_t *)&cmd_config_burst,
>  	(cmdline_parse_inst_t *)&cmd_config_thresh,
>  	(cmdline_parse_inst_t *)&cmd_config_threshold, diff --git
> a/doc/guides/rel_notes/release_21_05.rst
> b/doc/guides/rel_notes/release_21_05.rst
> index 23f7f0b..8077573 100644
> --- a/doc/guides/rel_notes/release_21_05.rst
> +++ b/doc/guides/rel_notes/release_21_05.rst
> @@ -69,6 +69,8 @@ New Features
> 
>    * Added command to display Rx queue used descriptor count.
>      ``show port (port_id) rxq (queue_id) desc used count``
> +  * Added command to cleanup a Tx queue's mbuf on a port.
> +    ``tx_done_cleanup port <port_id> <queue_id> <free_cnt>``
> 
> 
>  Removed Items
> diff --git a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> index f59eb8a..39281f5 100644
> --- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> +++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> @@ -272,6 +272,13 @@ and ready to be processed by the driver on a given RX
> queue::
> 
>     testpmd> show port (port_id) rxq (queue_id) desc used count
> 
> +cleanup txq mbufs
> +~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +Request the driver to free mbufs currently cached by the driver for a
> +given port's Tx queue::
> +   testpmd> tx_done_cleanup port (port_id) (queue_id) (free_cnt)
> +
>  show config
>  ~~~~~~~~~~~
> 
> --
> 2.7.4