[ntp:hackers] FreeBSD and serial port cards

Poul-Henning Kamp phk at phk.freebsd.dk
Tue Mar 6 08:01:59 PST 2007


In message <200703061556.l26FuR0Q002553 at ring.wraith.sf.ca.us>, gnu not unix wri
tes:
>In message <20070306101951.A23D7BE05 at ip-64-139-1-69.sjc.megapath.net> you write
>:
>
>>Linux has a ASYNC_LOW_LATENCY flag.  The parse driver sets it.  
>>ntp_refclock.c doesn't.
>
>It can be set in userland with the "setserial" utility.

>./setserial /dev/ttyS0 low_latency
>
>>What do FreeBSD geeks do if they want lower latency?
>
>For 5.4, recompile a kernel (cough) with a yourconfig.hints
>that has:
>
>hint.sio.0.flags="0x2"

You don't need to recompile the kernel, hints can be set
in the loader (/boot/loader.conf)


-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.


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