Re: [gpsd-dev] gpsd using excessive cpu

[Jon Schlueter]

one approach would be a dead time delay if we received fewer
than X bytes delay by long enough to get X bytes next time.  I
think there were attempts at this a while back on this list.  try

searching through the archives.

but a sane approach if you want a workaround would be 1-50 ms
sleep at the bottom of the read loop.  this would give it a reasonable
balance between snappy receives and not getting behind.  Too much

and gpsd get's behind because it needs to read multiple messages
per second, to little and it burns CPU if you have the bug in the
underlying drivers.

Jon

On Tue, Nov 17, 2015 at 3:14 PM, sean d'epagnier <address@hidden> wrote:

Now, I am trying to reproduce it, but not having much luck.

I have always seen this problem appear when I'm on passage.  I notice
gpsd is using excessive cpu.  At this point I am somewhere in the
ocean far from land and have been sailing 10-15 days and gpsd running
the whole time.  I am traveling 4-5 knots on average.  When I
restarted gpsd it immediately consumed too much cpu, so to me this
shows it is possibly a bug in the serial layer not gpsd as raymond
suggested.   I will leave my computer running for a few days to try to
reproduce, but after only 24 hours I don't see the problem yet.

Sean

On 11/17/15, Eric S. Raymond <address@hidden> wrote:
> sean d'epagnier <address@hidden>:
>> Maybe it is like you suggest returning even when there is not any
>> data.
>
> This has been seen on certain models of Samsung smartphones.  It can
> happen if there is a port bug in the Linux serial layer.
> --
>               <a href="" href="http://www.catb.org/~esr/" rel="noreferrer" target="_blank">http://www.catb.org/~esr/">Eric S. Raymond</a>
>