From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tariq Toukan Subject: Re: Page allocator order-0 optimizations merged Date: Wed, 29 Mar 2017 10:13:07 +0300 Message-ID: <4f9f5f04-039c-ce56-3456-4f04022f80e8@gmail.com> References: <83a0e3ef-acfa-a2af-2770-b9a92bda41bb@mellanox.com> <20170322234004.kffsce4owewgpqnm@techsingularity.net> <20170323144347.1e6f29de@redhat.com> <20170323145133.twzt4f5ci26vdyut@techsingularity.net> <779ab72d-94b9-1a28-c192-377e91383b4e@gmail.com> <1fc7338f-2b36-75f7-8a7e-8321f062207b@gmail.com> <2123321554.7161128.1490599967015.JavaMail.zimbra@redhat.com> <20170327105514.1ed5b1ba@redhat.com> <20170327143947.4c237e54@redhat.com> <20170327133212.6azfgrariwocdzzd@techsingularity.net> <0873b65b-2217-005d-0b42-4af6ad66cc0f@gmail.com> <26c4d7a4-c8a7-fbad-d2be-a5a90f6d93d3@gmail.com> <20170328202426.6485bd91@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: Mel Gorman , Pankaj Gupta , Tariq Toukan , netdev@vger.kernel.org, akpm@linux-foundation.org, linux-mm , Saeed Mahameed To: Jesper Dangaard Brouer Return-path: In-Reply-To: <20170328202426.6485bd91@redhat.com> Sender: owner-linux-mm@kvack.org List-Id: netdev.vger.kernel.org On 28/03/2017 9:24 PM, Jesper Dangaard Brouer wrote: > On Tue, 28 Mar 2017 19:05:12 +0300 > Tariq Toukan wrote: > >> On 28/03/2017 10:32 AM, Tariq Toukan wrote: >>> >>> >>> On 27/03/2017 4:32 PM, Mel Gorman wrote: >>>> On Mon, Mar 27, 2017 at 02:39:47PM +0200, Jesper Dangaard Brouer wrote: >>>>> On Mon, 27 Mar 2017 10:55:14 +0200 >>>>> Jesper Dangaard Brouer wrote: >>>>> >>>>>> A possible solution, would be use the local_bh_{disable,enable} instead >>>>>> of the {preempt_disable,enable} calls. But it is slower, using numbers >>>>>> from [1] (19 vs 11 cycles), thus the expected cycles saving is >>>>>> 38-19=19. >>>>>> >>>>>> The problematic part of using local_bh_enable is that this adds a >>>>>> softirq/bottom-halves rescheduling point (as it checks for pending >>>>>> BHs). Thus, this might affects real workloads. >>>>> >>>>> I implemented this solution in patch below... and tested it on mlx5 at >>>>> 50G with manually disabled driver-page-recycling. It works for me. >>>>> >>>>> To Mel, that do you prefer... a partial-revert or something like this? >>>>> >>>> >>>> If Tariq confirms it works for him as well, this looks far safer patch >>> >>> Great. >>> I will test Jesper's patch today in the afternoon. >>> >> >> It looks very good! >> I get line-rate (94Gbits/sec) with 8 streams, in comparison to less than >> 55Gbits/sec before. > > Just confirming, this is when you have disabled mlx5 driver > page-recycling, right? > > Right. This is a great result! >>>> than having a dedicate IRQ-safe queue. Your concern about the BH >>>> scheduling point is valid but if it's proven to be a problem, there is >>>> still the option of a partial revert. > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org