From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vn0-x22f.google.com (mail-vn0-x22f.google.com [IPv6:2607:f8b0:400c:c0f::22f]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 25F3B21F646; Sat, 20 Jun 2015 05:46:34 -0700 (PDT) Received: by vnbf62 with SMTP id f62so2200108vnb.1; Sat, 20 Jun 2015 05:46:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=/Vuhq3oE21PE7nwqX2XSuITdBDOO925WIMdNceZaEng=; b=YNjfG9hQ79pT2N2DHCOFI8DFuh/CWuoMQURfswjwSUYCduQE9aTPPAop21jT/K5ije 68+vQEhdGq2eZeqKVNrkxkw9WNBH0+rhljXIgm8afeWysM8qrDvQu6MnoOO2L2EiuW96 6kmAsI4kX5MFDKvnNlwfDvMXlDoWo3VBOdu3ZMmkNdCSyGflboKZ/Bx/9uHtf4aK1A/j 9Gjn/WLnzp5AOZuknakVe6P0Re/n3dwxfwXVWwYvIM9GwkxrV+e5Os6yWfpT71e9n+/i CG6APDfDN0YLzOQEU0KyjBFfYlXiMou75fpU9r0n8ujctbIhu/+mGCdFi9sx/urGFqVv QdLw== MIME-Version: 1.0 X-Received: by 10.52.251.107 with SMTP id zj11mr17136155vdc.96.1434804393645; Sat, 20 Jun 2015 05:46:33 -0700 (PDT) Received: by 10.52.12.167 with HTTP; Sat, 20 Jun 2015 05:46:33 -0700 (PDT) Received: by 10.52.12.167 with HTTP; Sat, 20 Jun 2015 05:46:33 -0700 (PDT) In-Reply-To: <5585545B.6040108@gmail.com> References: <5585545B.6040108@gmail.com> Date: Sat, 20 Jun 2015 15:46:33 +0300 Message-ID: From: Jonathan Morton To: Alan Jenkins Content-Type: multipart/alternative; boundary=001a1134d45e349d300518f26e7e Cc: cake@lists.bufferbloat.net, cerowrt-devel Subject: Re: [Cerowrt-devel] Latest build test - new sqm-scripts seem to work; "cake overhead 40" [still] didn't X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 20 Jun 2015 12:47:03 -0000 --001a1134d45e349d300518f26e7e Content-Type: text/plain; charset=UTF-8 It looks like your cake is new enough to support set associative hashing, but not the new overhead handling. The ATM flag was put in a long time ago. Looking at the code which grabs those options (cake_change), there doesn't seem to be a way to detect whether an unsupported option was provided by userspace, unless nla_parse_nested returns an error if the provided option struct would be overflowed. Clearly it doesn't, but just truncates it to fit. - Jonathan Morton --001a1134d45e349d300518f26e7e Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

It looks like your cake is new enough to support set associa= tive hashing, but not the new overhead handling. The ATM flag was put in a = long time ago.

Looking at the code which grabs those options (cake_change),= there doesn't seem to be a way to detect whether an unsupported option= was provided by userspace, unless nla_parse_nested returns an error if the= provided option struct would be overflowed. Clearly it doesn't, but ju= st truncates it to fit.

- Jonathan Morton

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