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([2a00:1fa0:8d7:7661:9091:2bdc:ea2:564d]) by smtp.gmail.com with ESMTPSA id t2sm7171945ljj.11.2019.12.09.02.16.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 09 Dec 2019 02:16:52 -0800 (PST) Subject: Re: [PATCH bpf-next 05/12] xsk: eliminate the RX batch size To: Magnus Karlsson , bjorn.topel@intel.com, ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, jonathan.lemon@gmail.com Cc: bpf@vger.kernel.org, saeedm@mellanox.com, jeffrey.t.kirsher@intel.com, maciej.fijalkowski@intel.com, maciejromanfijalkowski@gmail.com References: <1575878189-31860-1-git-send-email-magnus.karlsson@intel.com> <1575878189-31860-6-git-send-email-magnus.karlsson@intel.com> From: Sergei Shtylyov Message-ID: <8e243b69-0642-962e-41b4-8d0107b960c6@cogentembedded.com> Date: Mon, 9 Dec 2019 13:16:32 +0300 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 In-Reply-To: <1575878189-31860-6-git-send-email-magnus.karlsson@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Hello! On 09.12.2019 10:56, Magnus Karlsson wrote: > In the xsk consumer ring code there is a variable call RX_BATCH_SIZE Called? > that dictates the minimum number of entries that we try to grab from > the fill and Tx rings. In fact, the code always try to grab the ^^^^^^^^^^^^^^^^^^^^^ hm, are you sure there's no typo here? > maximum amount of entries from these rings. The only thing this > variable does is to throw an error if there is less than 16 (as it is > defined) entries on the ring. There is no reason to do this and it > will just lead to weird behavior from user space's point of view. So > eliminate this variable. > > With this change, we will be able to simplify the xskq_nb_free and > xskq_nb_avail code in the next commit. > > Signed-off-by: Magnus Karlsson [...] MBR, Sergei