On Thu, Jan 01, 2015 at 08:41:20PM -0600, Jeff Epler wrote: > Like Laurent Georget, I found by reading ntpd source > the scale is 2^16 (i.e., 1 ~= 1.5e-5 ppm, 65536 = 1ppm)
Yep, you wont find this documented in prose anywhere, not even at ntp.org. > - long freq; /* Frequency offset, as scaled PPM > + long freq; /* Frequency offset, in units of 2^-16 PPM > (parts per million) */ This wording is correct. IMHO, it is more understandable when you explain that this field is a fixed point number, with a 16 bit binary fraction. For example, see the comment in the function, ppb_to_scaled_ppm(), in Documentation/ptp/testptp.c. Thanks, Richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
