DPDK usage discussions
 help / color / mirror / Atom feed
From: Gaurav Bansal <zeebee48@gmail.com>
To: users@dpdk.org
Subject: [dpdk-users] packet drops seen once the no of rxd pkts reach the ring size
Date: Wed, 25 Sep 2019 16:09:13 +0530	[thread overview]
Message-ID: <CAFQQEmADxbT26BzBHpfeQgX-wHQxKZu8BiT7_5F1LSxbAekgdA@mail.gmail.com> (raw)

Hi all,
I am using dpdk 16.04 library to process the packets on a vmware vm (say
vm1). The traffic is sent through a client machine using apache bench. I am
observing an issue when the number of packets reaching the vmxnet3
interface reaches the descriptor ring size (set to 2048). Till 2048 all the
packets correctly reach the 'vmxnet3_recv_pkts' function.

But as the number of packets received reaches 2048, i start seeing some
retransmissions on the client side (as shown by tcpdump on client side).
Then i captured the packets on the esx host destined to vm1 and it shows
that all the original packets as well as the corresponding retransmissions
are reaching vm1. But somehow these packets fail to reach till
'vmxnet3_recv_pkts' function (this was found by putting the breakpoint in
'vmxnet3_recv_pkts' function and dumping the packet contents, which showed
that some packets don't reach here).

Now 'vmxnet3_recv_pkts' is the first function which reads the packets from
the descriptor ring and as the packets are not reaching till here, i am not
sure on how to debug this further. Possibly some issues related to the ring
initialization.... I enabled the init & RX logs for vmxnet3, but i don't
see any error logs as well. I also tried looking at rxq stats and it shows
0 all the time :
(gdb) p rxq->stats
$1 = {drop_total = 0, drop_err = 0, drop_fcs = 0, rx_buf_alloc_failure = 0}

Can anyone please provide some clues on how to debug this further ? Are
there any known issues related to this which have been fixed post 16.04
version ?
thanks,
gaurav

             reply	other threads:[~2019-09-25 10:39 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-25 10:39 Gaurav Bansal [this message]
2019-09-26  5:15 ` Gaurav Bansal
2019-09-26  5:16   ` Stephen Hemminger
2019-09-26  7:55     ` Gaurav Bansal
2019-09-28  8:47       ` [dpdk-users] packet drops with missing rxdIdx count in vmxnet3 Gaurav Bansal
2019-09-30  5:52         ` Gaurav Bansal
2019-09-30 14:59           ` Stephen Hemminger
2019-10-09  6:11             ` Gaurav Bansal

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:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

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

  git send-email \
    --in-reply-to=CAFQQEmADxbT26BzBHpfeQgX-wHQxKZu8BiT7_5F1LSxbAekgdA@mail.gmail.com \
    --to=zeebee48@gmail.com \
    --cc=users@dpdk.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).