Dear Simon Glass, In message <1305319923-9477-1-git-send-email-...@chromium.org> you wrote: > This defines the basics of a new boot time measurement feature. This allows > logging of very accurate time measurements as the boot proceeds, by using > an available microsecond counter.
Well, as long as we talk about microsecond resolution, I do not see the compelling advantage over the classic method of timing the output on the serial console port. At 115200 bps we have a "resolution" of better than 0.1 millisecond per character; this should be precise enough for most practical purposes. Logging and timing the serial output has a number of advantages over other solutions: - It requires zero code changes. You can run the production code and time it. You can use it without rebuilding / reinstalling the software, yes even without access to the source code. - It is completely platform, SoC and board idependent - we do not need to provide any specific timer servcies etc. which are inherently platform-dependent. - It does not cause execution overhead on the running system - it affects neither the execution speed not the memory footprint of the target under test. Can you please explain where your solution is better than this approach, i. e. which problems can be addressed with your code where the output timing method cannot be used, or where it is less efficient? 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: w...@denx.de "Oh dear, I think you'll find reality's on the blink again." - Marvin The Paranoid Android _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
