From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx.bisdn.de (mx.bisdn.de [185.27.182.31]) by dpdk.org (Postfix) with ESMTP id 78A562C7A for ; Thu, 12 Feb 2015 10:25:50 +0100 (CET) Received: from [172.16.251.227] (unknown [172.16.251.227]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx.bisdn.de (Postfix) with ESMTPSA id E1DC0A34E1; Thu, 12 Feb 2015 10:25:49 +0100 (CET) Message-ID: <54DC719B.6020009@bisdn.de> Date: Thu, 12 Feb 2015 10:25:47 +0100 From: Marc Sune User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.4.0 MIME-Version: 1.0 To: Bruce Richardson References: <1415358037-424-1-git-send-email-marc.sune@bisdn.de> <54D9F2A1.2040102@bisdn.de> <20150210132411.GE18684@bricha3-MOBL3> <54DB4A81.5040106@bisdn.de> <20150211142739.GA7720@bricha3-MOBL3> In-Reply-To: <20150211142739.GA7720@bricha3-MOBL3> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH] Adding RTE_KNI_PREEMPT configuration option X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Feb 2015 09:25:50 -0000 On 11/02/15 15:27, Bruce Richardson wrote: > On Wed, Feb 11, 2015 at 01:26:41PM +0100, Marc Sune wrote: >> On 11/02/15 02:54, Zhang, Helin wrote: >>>> -----Original Message----- >>>> From: Richardson, Bruce >>>> Sent: Tuesday, February 10, 2015 9:24 PM >>>> To: Marc Sune >>>> Cc: dev@dpdk.org; Zhang, Helin >>>> Subject: Re: [dpdk-dev] [PATCH] Adding RTE_KNI_PREEMPT configuration >>>> option >>>> >>>> On Tue, Feb 10, 2015 at 12:59:29PM +0100, Marc Sune wrote: >>>>> This patch of Nov 2014 hasn't been yet ACKed/NACKed. Could someone >>>>> please give some quick feedback? >>>>> >>>>> Thanks >>>>> marc >>>>> >>>>> On 07/11/14 12:00, Marc Sune wrote: >>>>>> This patch introduces CONFIG_RTE_KNI_PREEMPT flag. When set to 'no', >>>>>> KNI kernel thread(s) do not call schedule_timeout_interruptible(), >>>>>> which improves overall KNI performance at the expense of CPU cycles >>>> (polling). >>>>>> Default values is 'yes', maintaining the same behaviour as of now. >>>>>> >>>>>> Signed-off-by: Marc Sune >>>> Although a better option would be to have a runtime setting, this is still an >>>> improvement over what we have. >>>> >>>> Acked-by: Bruce Richardson >>>> >>>>>> --- >>>>>> config/common_linuxapp | 1 + >>>>>> lib/librte_eal/linuxapp/kni/kni_misc.c | 4 ++++ >>>>>> 2 files changed, 5 insertions(+) >>>>>> >>>>>> diff --git a/config/common_linuxapp b/config/common_linuxapp index >>>>>> 57b61c9..24b529d 100644 >>>>>> --- a/config/common_linuxapp >>>>>> +++ b/config/common_linuxapp >>>>>> @@ -380,6 +380,7 @@ CONFIG_RTE_LIBRTE_PIPELINE=y >>>>>> # Compile librte_kni >>>>>> # >>>>>> CONFIG_RTE_LIBRTE_KNI=y >>>>>> +CONFIG_RTE_KNI_PREEMPT=y >>>>>> CONFIG_RTE_KNI_KO_DEBUG=n >>>>>> CONFIG_RTE_KNI_VHOST=n >>>>>> CONFIG_RTE_KNI_VHOST_MAX_CACHE_SIZE=1024 >>>>>> diff --git a/lib/librte_eal/linuxapp/kni/kni_misc.c >>>>>> b/lib/librte_eal/linuxapp/kni/kni_misc.c >>>>>> index ba77776..e7e6c27 100644 >>>>>> --- a/lib/librte_eal/linuxapp/kni/kni_misc.c >>>>>> +++ b/lib/librte_eal/linuxapp/kni/kni_misc.c >>>>>> @@ -229,9 +229,11 @@ kni_thread_single(void *unused) >>>>>> } >>>>>> } >>>>>> up_read(&kni_list_lock); >>>>>> +#ifdef RTE_KNI_PREEMPT >>>>>> /* reschedule out for a while */ >>>>>> schedule_timeout_interruptible(usecs_to_jiffies( \ >>>>>> KNI_KTHREAD_RESCHEDULE_INTERVAL)); >>>>>> +#endif >>>>>> } >>>>>> return 0; >>>>>> @@ -252,8 +254,10 @@ kni_thread_multiple(void *param) >>>>>> #endif >>>>>> kni_net_poll_resp(dev); >>>>>> } >>>>>> +#ifdef RTE_KNI_PREEMPT >>>>>> schedule_timeout_interruptible(usecs_to_jiffies( \ >>>>>> KNI_KTHREAD_RESCHEDULE_INTERVAL)); >>>>>> +#endif >>>>>> } >>>>>> return 0; >>> As Bruce indicated, it would be better to do that at runtime, we can >>> add a config in struct rte_kni_conf, which will be copied to >>> struct rte_kni_device_info, then kernel space will know the configuration. >>> This way, we can enable/disable PREEMPT during KNI instance allocation time. >> As I said before, I see the point on having it at runtime and I agree. >> >> However, rte_kni_device_info is a struct that is per interface, not for the >> entire KNI subsystem, so it is kind of abusing to add a flag there when only >> will be used once, at bootstrap. To do it "properly" we should create a new >> ioctl() call IMHO. >> >>> Anyway, it can be done now or later. >> So, do we integrate the current patch, as acked by Bruce before? >> >> Marc > I'd like to see it go in, as a step forward, rather than not having it at all > because it's not quite perfect. > > One suggestion might be to have the compile time setting be > "CONFIG_RTE_KNI_PREEMPT_DEFAULT" rather than just "CONFIG_RTE_KNI_PREEMPT". This > would mean that we would not need to remove the setting later if we do add a > runtime option, as the setting only specified the default value rather than > the final value. :-) Ok. I can do this small change and sent v2 if we plan to integrate it and no one else wants to work on the runtime approach. I have no time right now to do a runtime setting patch. Marc > > /Bruce >