From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: bjarniig@hi.is Date: Mon, 9 Jan 2017 20:48:15 +0000 From: Bjarni Ingi Gislason To: J William Piggott Cc: Karel Zak , Sami Kerola , util-linux@vger.kernel.org Subject: Re: pull: hwclock 27 changes Message-ID: <20170109204815.GA22113@rhi.hi.is> References: <20161231214107.8658-1-kerolasa@iki.fi> <05e4405f-8096-9261-f9f2-d2c6b84675bc@gmx.com> <070fc458-ed69-a09c-11cc-42bb50fec888@gmx.com> <20170109113201.kt3mmxr7fqlwscdm@ws.net.home> <0e70d024-09f0-929f-f22f-ba29d3909e00@gmx.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <0e70d024-09f0-929f-f22f-ba29d3909e00@gmx.com> List-ID: On Mon, Jan 09, 2017 at 08:53:27AM -0500, J William Piggott wrote: > > [...] > > It is true, I suggested picking up the orphaned adjtimex(8) code as an > alternative to inserting it's functionality into hwclock(8). However, I > have since learned that the useful functions of adjtimex(8) are > available via the ntp utilities. The rest of its (dis)abilities have > the same problems we are seeing when reimplementing them into > hwclock(8). I think perhaps there were good reasons adjtimex(8) was > abandoned. Before, I believed adjtimex(8) might be a good fit for > util-linux, now I am not so sure. If someone demonstrates a useful > purpose for it I will change my position. > > I use "adjtimex" from the package in "Debian" to regulate the system clock. "Debian" has made some changes and I too, that I have not yet sent to them. I do not use NTP (ntpdate-debian) except when the system clock deviates more than 3 seconds from the right time. Then I update the system clock and correct the hardware clock accordingly and let "hwclock" calculate a new value for the drift (hwclock --systohc --update-drift). I have added a option '-A' to my version of "adjtimex", to compare the system and hardware clock about every 11 minutes (after a period of different long pauses of comparisons) and change frequency and tick to keep the system clock in compliance with the drift-corrected hardware clock. My computer is only on for a few hours a day. The hardware clock is never automatically updated on shutdown nor in the process of booting. N.B. The WARNING is caused by not updating the hardware clock but relying on the calculated drift to correct it. The offset of the system clock is now -0.692 seconds. The hardware clock was last updated 1st June 2016. The time between comparisons is 30 seconds multiplied by the first Fibonacci numbers, excluding a repeated number. Example of comparisons: ######## Start 1483984488 Mon Jan 9 17:54:48 UTC 2017 WARNING: CMOS time is 6.25 min behind system clock --- current --- -- suggested -- cmos time system-cmos error_ppm tick freq tick freq 1483984488 0.005348 9999 4012975 1483984518 0.005172 -5.9 9999 4012975 9999 4397870 WARNING: CMOS time is 6.25 min behind system clock --- current --- -- suggested -- cmos time system-cmos error_ppm tick freq tick freq 1483984519 0.002689 9999 4397870 1483984579 0.001900 -13.1 9999 4397870 9999 5259588 WARNING: CMOS time is 6.25 min behind system clock --- current --- -- suggested -- cmos time system-cmos error_ppm tick freq tick freq 1483984580 0.004296 9999 5259588 1483984670 0.002953 -14.9 9999 5259588 9999 6237539 WARNING: CMOS time is 6.25 min behind system clock --- current --- -- suggested -- cmos time system-cmos error_ppm tick freq tick freq 1483984671 0.009972 9999 6237539 1483984821 0.007474 -16.7 9999 6237539 10000 775398 WARNING: CMOS time is 6.25 min behind system clock --- current --- -- suggested -- cmos time system-cmos error_ppm tick freq tick freq 1483984822 -0.005831 10000 775398 1483985062 0.005554 47.4 10000 775398 9999 4220208 WARNING: CMOS time is 6.25 min behind system clock --- current --- -- suggested -- cmos time system-cmos error_ppm tick freq tick freq 1483985063 0.007414 9999 4220208 1483985453 0.000203 -18.5 9999 4220208 9999 5432026 WARNING: CMOS time is 6.25 min behind system clock --- current --- -- suggested -- cmos time system-cmos error_ppm tick freq tick freq 1483985454 0.001917 9999 5432026 1483986084 0.005602 5.8 9999 5432026 9999 5048743 WARNING: CMOS time is 6.25 min behind system clock --- current --- -- suggested -- cmos time system-cmos error_ppm tick freq tick freq 1483986085 0.016335 9999 5048743 1483986715 0.004416 -18.9 9999 5048743 9999 6288698 1483987345 0.023767 30.7 9999 6288698 9999 4275678 1483987975 0.027384 5.7 9999 4275678 9999 3899389 1483988605 0.015368 -19.1 9999 3899389 9999 5149314 1483989235 0.019079 5.9 9999 5149314 9999 4763352 1483989865 0.022661 5.7 9999 4763352 9999 4390684 1483990495 0.026288 5.8 9999 4390684 9999 4013452 1483991125 0.014275 -19.1 9999 4013452 9999 5263079 1483991755 0.033575 30.6 9999 5263079 9999 3255391 1483992385 0.021591 -19.0 9999 3255391 9999 4501993 1483993015 0.025241 5.8 9999 4501993 9999 4122356 The offset of the system clock is now -0.677 seconds. -- Bjarni I. Gislason