From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <dev-bounces@dpdk.org>
Received: from dpdk.org (dpdk.org [92.243.14.124])
	by inbox.dpdk.org (Postfix) with ESMTP id 0EFC0A055B;
	Tue, 25 Feb 2020 21:15:57 +0100 (CET)
Received: from [92.243.14.124] (localhost [127.0.0.1])
	by dpdk.org (Postfix) with ESMTP id 2084B1BF8D;
	Tue, 25 Feb 2020 21:15:56 +0100 (CET)
Received: from inbox.dpdk.org (xvm-172-178.dc0.ghst.net [95.142.172.178])
 by dpdk.org (Postfix) with ESMTP id 077E51F1C
 for <dev@dpdk.org>; Tue, 25 Feb 2020 21:15:55 +0100 (CET)
Received: by inbox.dpdk.org (Postfix, from userid 33)
 id BA9BBA055C; Tue, 25 Feb 2020 21:15:54 +0100 (CET)
From: bugzilla@dpdk.org
To: dev@dpdk.org
Date: Tue, 25 Feb 2020 20:15:54 +0000
X-Bugzilla-Reason: AssignedTo
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: DPDK
X-Bugzilla-Component: testpmd
X-Bugzilla-Version: 19.11
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: cfb@hpe.com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: Normal
X-Bugzilla-Assigned-To: dev@dpdk.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform
 op_sys bug_status bug_severity priority component assigned_to reporter
 target_milestone
Message-ID: <bug-409-3@http.bugs.dpdk.org/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://bugs.dpdk.org/
Auto-Submitted: auto-generated
X-Auto-Response-Suppress: All
MIME-Version: 1.0
Subject: [dpdk-dev] [Bug 409] testpmd sometimes does not correctly show
 RX-missed on Mellanox NICs
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

https://bugs.dpdk.org/show_bug.cgi?id=3D409

            Bug ID: 409
           Summary: testpmd sometimes does not correctly show RX-missed on
                    Mellanox NICs
           Product: DPDK
           Version: 19.11
          Hardware: All
                OS: All
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: testpmd
          Assignee: dev@dpdk.org
          Reporter: cfb@hpe.com
  Target Milestone: ---

When running testpmd using the Mellanox driver (mlx5), the value shown for
RX-missed will overflow and show an extremely large value at times. This
appears to occur when
/sys/devices/.../inifiband/mlx5_*/ports/*/hw_counters/out_of_buffer rolls o=
ver.
This value is an unsigned 32 bit and testpmd uses an unsigned 64 bit to sto=
re
the value. The initial value is read when testpmd is started, then a new va=
lue
is read while it is running. If the value read is less than the initial read
(after a rollover occurs), the difference will result in a negative value (=
or
in the case of unsigned storage, an extremely large value).

The calculation occurs in mlx5_stats_get():

        mlx5_read_ib_stat(priv, "out_of_buffer", &tmp.imissed);
        tmp.imissed -=3D priv->stats_ctrl.imissed_base;

Where the stored value, priv->stats_ctrl.imissed_base, contains a larger va=
lue
than the value stored in tmp.imissed.

Two possible solutions are to change the Mellanox drivers to use an unsigne=
d 64
bit value for out_of_buffer in sysfs (so that it doesn't rollover), or to
modify the mlx5 code to account for the rollover.

--=20
You are receiving this mail because:
You are the assignee for the bug.=