From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Denk Date: Sun, 28 Sep 2014 00:21:49 +0200 Subject: [U-Boot] [PATCH] tools: mkimage can read input on /dev/stdin In-Reply-To: <201409280001.26383.marex@denx.de> References: <20140927215655.365B9380044@gemini.denx.de> <201409280001.26383.marex@denx.de> Message-ID: <20140927222150.03C49380185@gemini.denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Dear Marek, In message <201409280001.26383.marex@denx.de> you wrote: > > > Can you please provide values for the size of the binary and the > > execution time? > > > > It's not really critical, but I'd like to understand the impact of > > your changes. You use case is pretty exotic, so it seems a valid > > question to me to try to understand what the extended functionality > > costs. > > Won't it be better to focus on the overall concept first and dig in the finer > details later ? > > I think right now, the question is -- do we want to support stdin as a source of > payload for mkimage or not at all? The general approach to new features in U-Boot is: 1) is it useful at least to some? and 2) does it not hurt others? Re 1), I think the use case is pretty exostic, but apparently there is at least one user for that. Re 2), we need some numbers. Plain mmap() on a regular file is supposed to be the fastest possible I/O method in a Unix OS, so we should understand how much a change costs, or if it makes sense to provide different implementations depending on input type (read() for stdin vs. mmap() for regular files). Or if the differences are so small that this is all not worth the time we spend here. Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de One difference between a man and a machine is that a machine is quiet when well oiled.