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[85.223.209.22]) by smtp.gmail.com with ESMTPSA id o14sm2425534lfl.41.2019.02.25.05.24.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Feb 2019 05:24:25 -0800 (PST) Subject: Re: [Xen-devel] xen/evtchn and forced threaded irq To: Julien Grall , Boris Ostrovsky Cc: Juergen Gross , Stefano Stabellini , Andrew Cooper , "linux-kernel@vger.kernel.org" , Jan Beulich , xen-devel , Dave P Martin References: <5e256d9a-572c-e01e-7706-407f99245b00@arm.com> <20190220000209.GA4091@localhost.localdomain> <21214d47-9c68-e6bf-007a-4047cc2b02f9@oracle.com> <8f7445d7-fa50-f3e9-44f5-cc2aebd020f4@arm.com> <15bc52cb-82d8-4d2c-e5a8-c6ae8de90276@oracle.com> <5df8888a-4a29-fccd-bac2-a9c170244029@arm.com> From: Oleksandr Andrushchenko Message-ID: <13a9616c-2d9a-f90b-3358-f2dcadbbb64d@gmail.com> Date: Mon, 25 Feb 2019 15:24:24 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/22/19 3:33 PM, Julien Grall wrote: > Hi, > > On 22/02/2019 12:38, Oleksandr Andrushchenko wrote: >> On 2/20/19 10:46 PM, Julien Grall wrote: >>> Discussing with my team, a solution that came up would be to >>> introduce one atomic field per event to record the number of event >>> received. I will explore that solution tomorrow. >> How will this help if events have some payload? > > What payload? The event channel does not carry any payload. It only > notify you that something happen. Then this is up to the user to > decide what to you with it. Sorry, I was probably not precise enough. I mean that an event might have associated payload in the ring buffer, for example [1]. So, counting events may help somehow, but the ring's data may still be lost > > Cheers, > [1] https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=xen/include/public/io/displif.h;h=cc5de9cb1f35dedc99c866d73d086b19e496852a;hb=HEAD#l756