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From:   Cong Wang <xiyou.wangcong@gmail.com>
Date:   Wed, 8 Jul 2020 13:16:22 -0700
Message-ID: <CAM_iQpVZ4_AEV6JR__u-ooF7-=ozABVr_XPXGqwj2AK-VM1U5w@mail.gmail.com>
Subject: Re: Packet gets stuck in NOLOCK pfifo_fast qdisc
To:     Paolo Abeni <pabeni@redhat.com>
Cc:     Josh Hunt <johunt@akamai.com>,
        Jonas Bonn <jonas.bonn@netrounds.com>,
        Michael Zhivich <mzhivich@akamai.com>,
        David Miller <davem@davemloft.net>,
        John Fastabend <john.fastabend@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Kernel Network Developers <netdev@vger.kernel.org>
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On Tue, Jul 7, 2020 at 7:18 AM Paolo Abeni <pabeni@redhat.com> wrote:
> So the regression with 2 pktgen threads is still relevant. 'perf' shows
> relevant time spent into net_tx_action() and __netif_schedule().

So, touching the __QDISC_STATE_SCHED bit in __dev_xmit_skb() is
not a good idea.

Let me see if there is any other way to fix this.

Thanks.