sys_linux: stop sticking ticks as workaround for old kernels

Drop the old workaround avoiding small changes in ticks needed to avoid
frequency steps due to inexact scaling of frequency vs ticks in kernels
before 2.6.18. chrony doesn't support such old kernels anymore.

diff --git a/sys_linux.c b/sys_linux.c
index 58b20a6390d93764f104d36899ccffd1ef21ed1f..50ed09f5eda007c9e3d90877705af5c0e42107cf 100644 (file)
--- a/sys_linux.c
+++ b/sys_linux.c
@@ -139,21 +139,6 @@ set_frequency(double freq_ppm)
   int required_delta_tick;
 
   required_delta_tick = round(freq_ppm / dhz);
-
-  /* Older kernels (pre-2.6.18) don't apply the frequency offset exactly as
-     set by adjtimex() and a scaling constant (that depends on the internal
-     kernel HZ constant) would be needed to compensate for the error. Because
-     chronyd is closed loop it doesn't matter much if we don't scale the
-     required frequency, but we want to prevent thrashing between two states
-     when the system's frequency error is close to a multiple of USER_HZ.  With
-     USER_HZ <= 250, the maximum frequency adjustment of 500 ppm overlaps at
-     least two ticks and we can stick to the current tick if it's next to the
-     required tick. */
-  if (sys_hz <= 250 && (required_delta_tick + 1 == current_delta_tick ||
-                        required_delta_tick - 1 == current_delta_tick)) {
-    required_delta_tick = current_delta_tick;
-  }
-
   required_freq = -(freq_ppm - dhz * required_delta_tick);
   required_tick = nominal_tick - required_delta_tick;