From: Sudarsana Reddy Kalluru <skalluru@marvell.com>
To: Guilherme Piccoli <gpiccoli@canonical.com>,
"jay.vosburgh@canonical.com" <jay.vosburgh@canonical.com>
Cc: GR-everest-linux-l2 <GR-everest-linux-l2@marvell.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Ariel Elior <aelior@marvell.com>
Subject: RE: [EXT] [PATCH V2] bnx2x: Prevent ptp_task to be rescheduled indefinitely
Date: Wed, 26 Jun 2019 08:25:05 +0000 [thread overview]
Message-ID: <MN2PR18MB2528569269272880338B8E4CD3E20@MN2PR18MB2528.namprd18.prod.outlook.com> (raw)
In-Reply-To: <CAHD1Q_y5wWqOkPaC+JsuGMfBHbwPHbQF93Y-+06Nck=HKrif2g@mail.gmail.com>
> -----Original Message-----
> From: Guilherme Piccoli <gpiccoli@canonical.com>
> Sent: Wednesday, June 26, 2019 1:56 AM
> To: Sudarsana Reddy Kalluru <skalluru@marvell.com>;
> jay.vosburgh@canonical.com
> Cc: GR-everest-linux-l2 <GR-everest-linux-l2@marvell.com>;
> netdev@vger.kernel.org; Ariel Elior <aelior@marvell.com>
> Subject: Re: [EXT] [PATCH V2] bnx2x: Prevent ptp_task to be rescheduled
> indefinitely
>
> Sudarsana, let me ask you something: why does the register is reading value
> 0x0 always in the TX timestamp routine if the RX filter is set to None? This is
> the main cause of the thread reschedule thing.
The register value of zero indicates there is no pending Tx timestamp to be read by the driver.
FW writes/latches the Tx timestamp for PTP event packet in this register. And it does the latching only if the register is free.
In this case user/app look to be requesting the Timestamp (via skb->tx_flags) for non-ptp Tx packet. In the Tx path, driver schedules a thread for reading the Tx timestamp,
bnx2x_start_xmit()
{
if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP))
schedule_work(&bp->ptp_task);
}
FW seem to be not timestamping the packet at all and driver is indefinitely waiting for it.
>
> Of course this thread thing is important to fix, but I was discussing with my
> leader here and we are curious on the reasoning the register is getting 0x0.
>
> Thanks in advance,
>
>
> Guilherme
next prev parent reply other threads:[~2019-06-26 8:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 22:23 [PATCH V2] bnx2x: Prevent ptp_task to be rescheduled indefinitely Guilherme G. Piccoli
2019-06-25 4:01 ` [EXT] " Sudarsana Reddy Kalluru
2019-06-25 12:55 ` Guilherme Piccoli
2019-06-25 20:25 ` Guilherme Piccoli
2019-06-26 8:25 ` Sudarsana Reddy Kalluru [this message]
2019-06-26 20:24 ` Guilherme Piccoli
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=MN2PR18MB2528569269272880338B8E4CD3E20@MN2PR18MB2528.namprd18.prod.outlook.com \
--to=skalluru@marvell.com \
--cc=GR-everest-linux-l2@marvell.com \
--cc=aelior@marvell.com \
--cc=gpiccoli@canonical.com \
--cc=jay.vosburgh@canonical.com \
--cc=netdev@vger.kernel.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).