Re: serial flow control appears broken

Lee Howard
2007-08-04T18:21:20Z

Ray Lee wrote:

>On 7/27/07, Lee Howard <faxguy@howardsilvan.com> wrote:
>
>
>>Curiously, the session at 38400 bps that skipped 858 bytes... coincided,
>>not just in sequence but also in precice timing within the session, with
>>a small but noticeable disk load that I caused by grepping through a
>>hundred session logs. (I can't reproduce it easily, though, because of
>>disk caching.)
>>
>>
>
>`echo 1 > /proc/sys/vm/drop_caches` will clear out most (all?) of what
>the kernel has cached from the drive. It's there just for this kind of
>repeatability of tests...
>

And in repeat tests it is quite evident that IDE disk activity is,
indeed, at least part of the problem. As IDE disk activity increases an
increased amount of data coming in on the serial port goes missing.

Thanks,

Lee.