This is a simple servo that provides the NTP SHM reference clock. It
doesn't make any clock adjustments and it always returns with the
unlocked state. It writes all samples to the SHM segment and another
process (e.g. chronyd or ntpd) is needed to read the samples and
actually synchronize the clock. The SHM segment number is set to the PTP
domain number to allow multiple SHM reference clocks running at the same
time.
This is mainly useful when other time sources are available on the
system (e.g. NTP, hardware reference clocks, or other PTP domains)
and a fallback to/from PTP is needed.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Most PHC drivers implement stepping (ADJ_SETOFFSET) by reading the
clock, adjusting the value by the offset and writing it back. This is
not perfectly accurate and if the operation is slow (e.g. due to PCIe
latencies), the error can be in microseconds.
Increase the default first step threshold from 100 nanoseconds to 20
microseconds to step only when the initial offset is larger than
the error in the step.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
This servo uses linear regression to estimate current time and
frequency error. The number of points used in the regression is
variable (from 4 to 64 in powers of 2) and is selected by a long-term
statistic of the prediction error.
Future improvements could include tracking of sudden frequency changes
(e.g. due to temperature variations), better stability of the error
statistic when a large offset is corrected, options to set the speed of
the adaptation, minimum and maximum number of points, or an option to
prefer frequency accuracy over time accuracy.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
These settings will be useful for all implemented servos, so move them
to the common servo code to avoid duplication. The configuration options
are renamed, but the they can be still set by their old names.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
When peer delay is < min_neighbor_prop_delay the port is flagged
as non 802.1AS capable. min_neighbor_prop_delay defaults to -20ms.
Signed-off-by: Delio Brignoli <dbrignoli@audioscience.com>
Add new options delay_filter and delay_filter_length to select the
filter and its length. They set both the clock delay filter and the port
peer delay filter. The default is now moving median with 10 samples.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Check the sanity of the synchronized clock by comparing its uncorrected
frequency with the system monotonic clock. When the measured frequency
offset is larger than the value of the sanity_freq_limit option (20% by
default), a warning message will be printed and the servo will be reset.
Setting the option to zero disables the check.
This is useful to detect when the clock is broken or adjusted by another
program.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Instead of using fixed constants, set them by the following formula from
the current sync to allow good performance of the servo even when the
sync interval changes in runtime and to avoid instability.
kp = min(kp_scale * sync^kp_exponent, kp_norm_max / sync)
ki = min(ki_scale * sync^ki_exponent, ki_norm_max / sync)
The scale, exponent and norm_max constants are configurable. The
defaults are chosen so there is no change to the previous default
constants of the servo with one second sync interval. The automatic
adjustment can be disabled by setting the pi_proportional_const and
pi_integral_const options to a non-zero value, but stability of the
servo is always enforced.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
This patch adds support for using the configured_pi_f_offset servo option to ptp4l.
If "pi_f_offset_const 0.0" is specified in the config file, stepping on the first
update is prevented. If any other positive value is specified, stepping on the
first update occurs when the offset is larger than the specified value.
change since v1
- add the new option to default.cfg and gPTP.cfg
Signed-off-by: Ken ICHIKAWA <ichikawa.ken@jp.fujitsu.com>
Options without parameters are now grouped together at the beginning of line
for better legibility.
Signed-off-by: Libor Pechacek <lpechacek@suse.cz>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
The option sets an additional limit to the hardware limit. It's disabled
if set to zero. The default is 900000000 ppb.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
This patch modifies sk_receive in order to use poll() on POLLERR instead of the
tryagain loop as this resolves issues with drivers who do not return timestamps
quickly enough. It also resolves the issue of wasting time repeating every
microsecond. It lets the kernel sleep our application until the data or timeout arrives.
This change also replaces the old tx_timestamp_retries config value with
tx_timestamp_timeout specified in milliseconds (the smallest length of time poll
accepts). This does have the side effect of increasing the minimum delay before
missing a timestamp by up to 1ms, but the poll should return sooner in the
normal case where a packet timestamp was not dropped.
This change vastly improves some devices and cleans the code up by simplifying a
race condition window due to drivers returning tx timestamp on the error queue.
[ RC - removed the unused 'try_again' variable. ]
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Add kernel_leap option for ptp4l and -x option for phc2sys to disable
setting of the STA_INS/STA_DEL bit to slowly correct the one-second
offset by servo.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Handle reception of >=3 sequential multiple pdelay responses from
distinct peers as a fault of type FT_BAD_PEER_NETWORK.
Signed-off-by: Delio Brignoli <dbrignoli@audioscience.com>
Add new options to ptp4l and phc2sys to print summary statistics of the
clock instead of the individual samples.
[ RC - Fix () function prototype with (void).
- Use unsigned for sample counter.
- Fix over-zealous line breaks. ]
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
A timeout of 15 seconds is not always acceptable, make it configurable.
By popular consensus, instead of using a linear number of seconds, use
the 2^N format for the time interval, just like the other intervals in
the PTP data sets. In addition to numeric values, let the configuration
file support 'ASAP' to have the fault reset immediately.
[RC - moved the handling of special case tmo=0 and added a break out
of the fd event loop in case the fds have been closed.
- changed the linear seconds option to log second instead.
- changed the commit message to reflect the final version. ]
Signed-off-by: Delio Brignoli <dbrignoli@audioscience.com>
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
It seems with some cards the current default of 2 is too small, increase
the number to prevent users from having to investigate the EAGAIN error
messages.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Miroslav Lichvar
Delio Brignoli
Richard Cochran
Ken ICHIKAWA
Libor Pechacek
Jacob Keller
Geoff Salmon