From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTP id 3400FAEC for ; Mon, 5 May 2014 13:20:44 +0000 (UTC) Received: from mho-01-ewr.mailhop.org (mho-03-ewr.mailhop.org [204.13.248.66]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id A66201FB23 for ; Mon, 5 May 2014 13:20:42 +0000 (UTC) Date: Mon, 5 May 2014 07:31:27 -0400 From: Jason Cooper To: Guenter Roeck Message-ID: <20140505113127.GJ28159@titan.lakedaemon.net> References: <53662254.9060100@huawei.com> <53664E31.6030706@roeck-us.net> <536709BA.7070809@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <536709BA.7070809@roeck-us.net> Cc: Josh Boyer , lizf.kern@gmail.com, ksummit-discuss@lists.linuxfoundation.org Subject: Re: [Ksummit-discuss] [CORE TOPIC] stable issues List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sun, May 04, 2014 at 08:47:06PM -0700, Guenter Roeck wrote: > This may be seen as somewhat strong definition of the term "severe", > but in my work environment the attitude is to never update the kernel under > any circumstances. Or, in other words, it is quite hostile to someone who > advocates following upstream kernel releases. Each new bug, as minor as it > may be in a practical sense, is seen as argument (or ammunition) against > kernel updates. Note that this specifically includes performance regressions, > as minor as they may be. Given that, I would love to see Fengguang's > performance tests run on stable releases, simply because that would give me > confidence (and proof) that no performance regressions were introduced. Along this line, I keep coming back to an idea that I really need to implement. Say your shop is running v3.12.3, and you'd like to migrate to v3.12.7 because of a bugfix for your subsystem. I imagine it would make the argument easier if you could quantify the changes from v3.12.3 to v3.12.7 relevant to your kernel config. eg: $ git diff v3.12.3..v3.12.7 | ./scripts/diff-filter mydefconfig (no, diff-filter doesn't exist, yet) I could also see using ./scripts/objdiff for this as well. Anything that would help the engineer quantify the differences between the two releases so he could ask the question, "Show me *which* change you're uncomfortable with." That's a much better position to be in than, "I swear, the -stable process is legit. You can trust a bunch of people you've never met who won't suffer any repercussions if our product fails." This assumes a fairly minimal config, of course. ;-) thx, Jason.