Re: [gpsd-dev] Fwd: Re: gpsd for time sync on Ubuntu remix too hard for normals - how to improve?

[Lisandro Damián Nicanor Pérez Meyer]

El miércoles, 8 de mayo de 2019 14:16:28 -03 Gary E. Miller escribió:
> Yo Lisandro!
> 
> On Wed, 08 May 2019 11:33:02 -0300
> 
> Lisandro Damián Nicanor Pérez Meyer <address@hidden> wrote:
> > El miércoles, 8 de mayo de 2019 08:21:02 -03 Greg Troxel escribió:
> > [snip]
> > 
> > > My memory is fuzzy, but I'm pretty sure I''ve seen macs (macos)
> > > enter sleep in the middle of a huge compilation.  My impression has
> > > been that entering sleep is about timeouts from keyboard/mouse and
> > > the implied human.
> > > 
> > > Systems have all sorts of background processes, like syslog and
> > > cron. So this may well be true, but it doesn't seem obviously
> > > sensible.
> > > 
> > > Hence my notion of something specific that can be looked up and the
> > > details read about.
> > 
> > I also agree it does not strictly depends upon gpsd, so I changed the
> > wording to "might keep".
> > 
> > In fact I would like to know a single case in which this might happen.
> 
> I hate sleep and suspend, so I'm the wrong guy to test it.
> 
> I tried to google it, but instead I found lots of references to how to
> prevent sleeping in Linux...
> 
> Can someone that uses sleep test this?
> 
> I can't see an obvious difference from the command line:
> 
> # gps -n /dev/ttyACM0
> 
> # ps -el | fgrep gpsd
> F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
> 5 S 65534 26585     1  0  70 -10 -  3512 core_s ?        00:01:07 gpsd
> 
> # killall gpsd
> 
> # gpsd /dev/ttyACM0
> 
> # ps -el | fgrep gpsd
> F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
> 5 S 65534 20269     1  0  70 -10 -  1462 core_s ?        00:00:00 gpsd
> 
> Both cases the gpsd is in interruptable sleep (S) waiting on "core_s".
> Then wakes up periodically to check for inbound connections.  With -n
> case also wakes up to check the serial in buffer.
> 
> top shows a increase with -n on a RasPi 3 from 0% to 1 or 2% CPU load.
> 
> I know any long term process using 2% on my android will get me nags
> about sleep being prevented.
> 
> On Linux there are vague references to "CPU must be idle" to enter long
> term sleep/hibernate.  Unclear if 1% is close enough to idle...
> 
> Can someone that uses sleep test this?

I'll see to get a laptop in which to test this, mine is already 10+yo and it's 
battery it's... dead.

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