From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <lijun422@gmail.com>
Received: from mail-wm0-f45.google.com (mail-wm0-f45.google.com [74.125.82.45])
 by dpdk.org (Postfix) with ESMTP id 735DE1D90
 for <users@dpdk.org>; Tue, 28 Nov 2017 03:24:37 +0100 (CET)
Received: by mail-wm0-f45.google.com with SMTP id b189so38707051wmd.5
 for <users@dpdk.org>; Mon, 27 Nov 2017 18:24:37 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
 h=mime-version:in-reply-to:references:from:date:message-id:subject:to
 :cc; bh=beFUQ8yjNuxEjVhwPO2aCiCHwuAVm3cLhYbcoY9NRso=;
 b=WXotg7Zb4oA+EBClJOXKqBKFr/nm54RuAylFUWb2g948v3O/uQf8Ts/oEaU61co9wq
 83YNWX4AcJWyLXL4bXsmOHxTq1bRNtZR77x4NYiLydlYM0PhUURTrOfnSOrZSDcAhSSO
 pImhUS6quduD9yf8xCNnTZ1PL6/eFnWuHWUMooH8QYEGqkb5wRQU5z2T63gykJYMeUgu
 18POE0OeDFUaDki2ENch4WSDIBiIONo0m+KLTyMmrTxZ89CCwT+pevITQyrDrQnByk94
 nuYNxsfhA8un8cbfAo2DSGpucEYuzck41ZTIoxoE3ArVCDDScwlhY3Z+sZQk3Uj5YUTM
 wkvw==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20161025;
 h=x-gm-message-state:mime-version:in-reply-to:references:from:date
 :message-id:subject:to:cc;
 bh=beFUQ8yjNuxEjVhwPO2aCiCHwuAVm3cLhYbcoY9NRso=;
 b=IBXZmqDu3zmqXg3jF+k+tNToWqDiRSqxA8gzlslXeg87cB370zyX/fW/ZfiMJA25qS
 KrhqDsiqGLV/Sm2jf4zTFf8XF8lgS1+lzNHiAH+dA/25ipbqMU9LTMq61tFD3TZuGGZg
 qRutzLazt5P265kEOd90d5qV8CHVcmFsv54HzhCDRMszjUxLAVj0+feMx9YFZLrmYp6l
 2PyCO8T66KBE1DRyHZX6iZKwYretjwqjYB1yPKoyPhB3U75SmLjUC/SLk3Oe1FSfTlBi
 jzrPapCYRM0JMCY5pq6kF8Jsv8r5hbwEeZFMTcErk2WCmpffKpN5SNdCiFVW1q9312y9
 veyQ==
X-Gm-Message-State: AJaThX70AO2EGgctUBS+oBaukV3vJQPF5MMfivjN6IN1fagE7hEWMriI
 5NVAXGPGJaQmUHDBTXyNaCqzepa1AELx4iGOjTYCGw==
X-Google-Smtp-Source: AGs4zMbuyPHYH4HjH5Zhbwo7DhBwwE99mi95hz5EdGZb7mP2h1qXASLYg8aFF2gR9XZ5bzDGSFV2EHqzEnm2ZnHGHHA=
X-Received: by 10.28.108.11 with SMTP id h11mr16978909wmc.28.1511835877161;
 Mon, 27 Nov 2017 18:24:37 -0800 (PST)
MIME-Version: 1.0
Received: by 10.223.188.67 with HTTP; Mon, 27 Nov 2017 18:24:36 -0800 (PST)
In-Reply-To: <CACVZbxrg1-CE5wQF=YwAHJJaWFK63N5n2j-SEJCB7RVwmzR2fw@mail.gmail.com>
References: <CACVZbxroP9h7oMAmR8L1EkwTVLYv++SV+Lwew-mhcfUeUAJc_A@mail.gmail.com>
 <CADNuJVr3O+h-mhiL8=2tJtk0wCecVE_4XfaCog0xpVz10yc5Ew@mail.gmail.com>
 <CACVZbxrg1-CE5wQF=YwAHJJaWFK63N5n2j-SEJCB7RVwmzR2fw@mail.gmail.com>
From: junlee <lijun422@gmail.com>
Date: Tue, 28 Nov 2017 10:24:36 +0800
Message-ID: <CACVZbxodcAyY1ngqwvZ3cTZVprLmufE3BtxhE_j8t=Z1uzBvWg@mail.gmail.com>
To: Jay Rolette <rolette@infinite.io>
Cc: users <users@dpdk.org>
Content-Type: text/plain; charset="UTF-8"
X-Content-Filtered-By: Mailman/MimeDel 2.1.15
Subject: Re: [dpdk-users] KNI with RTE_KNI_PREEMPT_DEFAULT=n causes CPU
	soft-lockup
X-BeenThere: users@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: DPDK usage discussions <users.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/users>,
 <mailto:users-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/users/>
List-Post: <mailto:users@dpdk.org>
List-Help: <mailto:users-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/users>,
 <mailto:users-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Tue, 28 Nov 2017 02:24:37 -0000

We also tried to turn off the watchdog, then we got RCU stall.
INFO: rcu_sched self-detected stall on CPU

Is there any system configuration that should be made before setting
RTE_KNI_PREEMPT_DEFAULT to n?


2017-11-27 20:49 GMT+08:00 junlee <lijun422@gmail.com>:

> Hi Jay,
>
> Thanks.
> We have read the thread before, increasing HZ to 1000 helps, but we are
> looking for latency even less than 1ms.
> The DPDK version is 17.05.
>
> The kernel preempt setting is:
> CONFIG_PREEMPT_NONE=y
> # CONFIG_PREEMPT_VOLUNTARY is not set
> # CONFIG_PREEMPT is not set
>
> Seems the watchdog/x process could not get chance to run
> when schedule_timeout_interruptible() is not called.
>
> Thanks.
> BR//Wendy
>
> 2017-11-27 20:36 GMT+08:00 Jay Rolette <rolette@infinite.io>:
>
>> That shouldn't cause soft-lockups, but IIRC, there have been KNI bugs in
>> that past that would. Probably worth checking whatever version of DPDK you
>> are running vs. the tree for relevant fixes.
>>
>> Given what you are looking into, this thread may be of interest:
>>
>> http://dpdk.org/ml/archives/dev/2015-June/018858.html
>>
>> Jay
>>
>> On Sun, Nov 26, 2017 at 7:27 PM, junlee <lijun422@gmail.com> wrote:
>>
>>> Hi,
>>>
>>> We are testing KNI performance and finds the
>>> schedule_timeout_interruptible
>>> causes extra latency for packets.
>>>
>>> We tried to set RTE_KNI_PREEMPT_DEFAULT=n to reduce the latency, but ends
>>> up with CPU soft-lockup.
>>>
>>> Anybody knows how to make this work?
>>>
>>> static int
>>> kni_thread_single(void *data)
>>> {
>>> struct kni_net *knet = data;
>>> int j;
>>> struct kni_dev *dev;
>>>
>>> while (!kthread_should_stop()) {
>>> down_read(&knet->kni_list_lock);
>>> for (j = 0; j < KNI_RX_LOOP_NUM; j++) {
>>> list_for_each_entry(dev, &knet->kni_list_head, list) {
>>> kni_net_rx(dev);
>>> kni_net_poll_resp(dev);
>>> }
>>> }
>>> up_read(&knet->kni_list_lock);
>>> #ifdef RTE_KNI_PREEMPT_DEFAULT
>>> /* reschedule out for a while */
>>> schedule_timeout_interruptible(
>>> usecs_to_jiffies(KNI_KTHREAD_RESCHEDULE_INTERVAL));
>>> #endif
>>> }
>>>
>>> return 0;
>>> }
>>>
>>> Thanks.
>>>
>>
>>
>