DPDK usage discussions
 help / color / mirror / Atom feed
From: Stephen Hemminger <stephen@networkplumber.org>
To: fwefew 4t4tg <7532yahoo@gmail.com>
Cc: users@dpdk.org
Subject: Re: (AWS ENA NIC) queued v. out packets reported by any of the DPDK stats functions
Date: Tue, 15 Mar 2022 13:15:34 -0700
Message-ID: <20220315131534.1e717ff2@hermes.local> (raw)
In-Reply-To: <CA+Tq66UpwJ6B3Jztw5YHdScNsvyzVQ_iPfssU_WoPWj=CAo7Kg@mail.gmail.com>

On Tue, 15 Mar 2022 15:28:55 -0400
fwefew 4t4tg <7532yahoo@gmail.com> wrote:

> On DPDK head commit (917229) I have a simple program creating two TXQs each
> sending 15000 IPV4 UDP packets.
> As far as I can see there are no errors anymore. I have looked. I burst TX
> them in blocks of 15; rte_eth_tx_burst always returns 15.
> The lcores are launched with rte_eal_mp_remote_launch, and main() blocks
> until rte_eal_mp_wait_lcore() returns.
> However, at any time after rte_eal_mp_wait_lcore returns showing the number
> of out packets as per rte_eth_stats_get or xstats per rte_eth_xstats_get I
> see two things:
> - the reported number of queued packets per TXQ is always 15000
> - the number of out packets or "good packets" is close to 15000*2 but never
> 30000
> It appears like the TXQs still have work in-queue even after the lcore's
> thread returns and rte_eal_mp_wait_lcore returns. I've tried to
> rte_eth_tx_done_cleanup and/or rte_eth_dev_tx_queue_stop before I get the
> stats. That doesn't seem to help.
> The TXQ config is default except for checksum offloads:
> 000000.336378246 DEBUG reinvent_dpdk_initaws.cpp:1341 TXQ conf:
> {"tx_thresh": { "pthresh": 0, "hthresh": 0, "wthresh": 0 }, "tx_rs_thresh":
> 0, "tx_free_thresh": 0, "tx_deferred_start": 0, "tx_offloads": 00008006, }
> Is this expected behavior? I've look through code; I haven't seen clear
> signs of a TXQ oriented lcore flushed or waiting for the output queue to be
> actually written onto the wire before exiting.

No part of lcore_wait is related directly to TxQ. 
The TxQ runs asynchronously. If you have to check if packet was sent, the
you would need to use rte_eth_tx_descriptor_status().

But not all hardware supports this API; AWS ENA does not.

      reply	other threads:[~2022-03-15 20:15 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-15 19:28 fwefew 4t4tg
2022-03-15 20:15 ` Stephen Hemminger [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220315131534.1e717ff2@hermes.local \
    --to=stephen@networkplumber.org \
    --cc=7532yahoo@gmail.com \
    --cc=users@dpdk.org \


* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK usage discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror http://inbox.dpdk.org/users/0 users/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 users users/ http://inbox.dpdk.org/users \
	public-inbox-index users

Example config snippet for mirrors.
Newsgroup available over NNTP:

AGPL code for this site: git clone https://public-inbox.org/public-inbox.git