On Mon, May 16, 2011 at 3:55 PM, Wolfgang Denk <w...@denx.de> wrote: > Dear Graeme Russ, > > In message <BANLkTim7=-rza_l-dy0b-+adqv4ngol...@mail.gmail.com> you wrote: >> >> But at 9600 baud it is over 1ms - 9600 is still considered the lowest >> common denominator for serial comms for diagnostic output for a lot of >> devices such as industrial PLCs etc. > > I think in the last 5 years I have seen but 2 devices using 9600 bps. > All others appear to be using 115200 bps these days. > > And even at 9600 we're still close to millisecond reolution... > >> And in the field, you may be interested more in transient timing anomalies >> which may result from network issues if the device is obtaining an IP address >> or loading an image file. In such scenarios, you will need to log the boot >> timing of every boot, not just when a serial terminal is connected > > 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 > >> And finally, the lack of a serial port is a biggie - There are devices out >> there that do not have serial ports > > If they have a console interface, then the output can be time-stamped. See above Regards, Graeme _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
