[ntp:questions] Optimising NTP build for Raspberry Pi 2

juergen perlinger juergen.perlinger at t-online.de
Sat Mar 7 21:01:02 UTC 2015


On 03/07/2015 01:41 PM, Neil Green wrote:
> In an attempt to squeeze all I can out of a NTP and GPS/PPS setup on the Raspberry Pi 2 I’m starting to experiment with compile flags using GCC 4.8. Currently I have:
>
> CC="gcc-4.8" CFLAGS="-mcpu=cortex-a7 -mfpu=neon-vfpv4" ./configure --enable-NMEA --enable-ATOM --enable-linuxcaps --disable-all-clocks --disable-parse-clocks --disable-ipv6
>
> Will attempting to optimise the build like this have any positive impact on NTP in terms of precision, stability etc, or am I focussing on an area that will have no benefit?
Tweaking here can save you code size by omitting features you do not 
use, and it might save you execution cycles if the compiler can tailor 
the machine code as tight to the target as possible. But NTPD is not 
exactly a number crunching application or high volume data server, so 
you might end up with a diminishing return of invest.

IMHO the code size reduction is the most prominent potential benefit you 
can get. ('Potential' because I do not now how tight your RAM is 
crammed.) As others have mentioned, the affect on the operation itself 
is probably nonexistent -- the critical execution paths should mostly be 
in the kernel.

Oh, and your build time should go down. But I guess that's not what was 
foremost in your mind...

Cheers,
     Pearly



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