DPDK patches and discussions
 help / color / mirror / Atom feed
From: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
To: dev@dpdk.org
Cc: matan@mellanox.com, rasland@mellanox.com, thomas@monjalon.net,
Subject: [dpdk-dev] [PATCH v2] doc/mlx5: add timestamp upper limitation description
Date: Mon, 27 Jul 2020 15:51:04 +0000
Message-ID: <1595865064-12892-1-git-send-email-viacheslavo@mellanox.com> (raw)

Add description about Tx scheduling timstamp upper limit.
It timstamp exceed the value it is marked by PMD as being
into "too-distant-future" and not scheduled at all (is being
sent without any wait).

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
v1->v2: typo fix

 doc/guides/nics/mlx5.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
index 90202c0..b9bd3db 100644
--- a/doc/guides/nics/mlx5.rst
+++ b/doc/guides/nics/mlx5.rst
@@ -253,6 +253,13 @@ Limitations
   reported via device xstats to assist applications to detect the
   time-related problems.
+  The timestamp upper "too-distant-future" limit at the moment of invoking
+  the tx_burst routine can be estimated as ``tx_pp`` devarog (in nanoseconds)
+  multiplied by 2^23. Please note, for the testpmd txonly testcase the limit
+  is deduced from the expression::
+        (n_tx_descriptors / burst_size + 1) * inter_burst_gap
   There is no any packet reordering according timestamps is supposed,
   neither within packet burst, nor between packets, it is an entirely
   application responsibility to generate packets and its timestamps

             reply	other threads:[~2020-07-27 15:51 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-27 15:51 Viacheslav Ovsiienko [this message]
2020-08-05 15:26 ` [dpdk-dev] [PATCH v3] doc: add timestamp upper limitation in mlx5 guide Thomas Monjalon
2020-08-05 15:43   ` Thomas Monjalon

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=1595865064-12892-1-git-send-email-viacheslavo@mellanox.com \
    --to=viacheslavo@mellanox.com \
    --cc=dev@dpdk.org \
    --cc=ferruh.yigit@intel.com \
    --cc=matan@mellanox.com \
    --cc=rasland@mellanox.com \
    --cc=thomas@monjalon.net \


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

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/dev/0 dev/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 dev dev/ https://inbox.dpdk.org/dev \
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:

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