From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Denk Date: Mon, 16 May 2011 13:18:22 +0200 Subject: [U-Boot] [PATCH 0/4] Accurate boot time measurement In-Reply-To: References: <1305319923-9477-1-git-send-email-sjg@chromium.org> <20110515115317.56695DB7945@gemini.denx.de> <20110516055503.81F381491B07@gemini.denx.de> Message-ID: <20110516111822.D56D31491B07@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 Graeme Russ, In message you wrote: > > > time-stamping console output is not restricted to the serial port. It > > works as well with tty over USB, or netconsole, or even netconsole > > over USB. > > My point is, if the device reboots in the field, you cannot recover the > boot timing analysis as once it is streamed out it is gone forever Agreed. But so far I have never seen a need to perform boot time measurements on devices in the field without access to the console (serial, or usb or netconsole). In all my experience, such behaviour is pretty much deterministic and can be done in the lab, before shipping systems. The only way where I can imagine that the boot ime depends on the actual user environment is when booting from the network, but then again you can also run a network sniffer to measure this impact. I really wonder what the benefit of adding such code to U-Boot is. 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 Genitiv ins Wasser, weil's Dativ ist!