[ntp:questions] ntp-4.2.6p5 on Win 7 x64

Charles Elliott elliott.ch at comcast.net
Sat Jul 19 14:05:48 UTC 2014


> This performance is marginal for WSJTX.  I need 10ms offset or less after
> 15 minutes.

	One more time, this is what I have done to achieve sub-millisecond
accuracy (currently 0.092 offset and 0.033 jitter):

	Make sure you are using a recent version of NTPD; I am using ntpd
4.27p442, May 09, 10:14:35.18 (UTC -04:00) 2014 that I downloaded from
http://archive.ntp.org/ntp4/ntp-dev/ntp-dev-4.2.7p446.tar.gz, compiled with
Visual Studio Express 2013, and copied to C:\Program Files (x86)\NTP\bin,
after renaming the old bin directory.  Although compiling NTPD yourself is
not that hard it does take some experience; Harlan Stenn <stenn at ntp.org> may
have a pre-compiled for Windows version; consider asking.

	Enable HPET: run cmd as admin and paste "bcdedit /set {current}
useplatformclock Yes"; some people complain that the cost of reading the
HPET periodically outweighs its benefits, but I have not seen that.

	Put NTPD_USE_INTERP_DANGEROUS=1 in your system environment
variables.

	Do not use the pool servers!  They are mostly junk, are not well
attended and maintained, and in my experience their time is often
unacceptably variable.  Find stratum 1 and 2 (preferable) servers that are
geographically close to you (~ 50 - 75 miles), that provide consistent
offsets, and that are lightly loaded.

	Use iburst minpoll 4 maxpoll 5; in my area, I was never able achieve
fast synchronization and quick recovery from Internet congestion with
maxpoll 64.

	Use 5 to 9 external servers; weed out the ones that rarely make the
cut, but keep the number that are used up around 5.

	If the computers on your LAN must be consistent, then consider
Gigabyte Ethernet on the LAN.  Gigabyte Ethernet will work over good quality
Cat 5 cable, so all you may need is a new router.

	The faster your connection to the Internet, the less variable the
time you serve will be.  15 to 28 Mbps works well here.

	Please use a working email address.  It takes a long time to write
this stuff, only to have the email returned as undeliverable.

Charles Elliott

> -----Original Message-----
> From: questions-bounces+elliott.ch=comcast.net at lists.ntp.org
> [mailto:questions-bounces+elliott.ch=comcast.net at lists.ntp.org] On
> Behalf Of Nick
> Sent: Friday, July 18, 2014 4:09 PM
> To: questions at lists.ntp.org
> Subject: Re: [ntp:questions] ntp-4.2.6p5 on Win 7 x64
> 
> Brian
> 
> thanks for your useful reply...
> 
> On Fri, 18 Jul 2014 02:03:48 +0000, Brian Inglis wrote:
> 
> > Windows is using the MM timer as its high precision time source, not
> PM
> > timer, HPET or TSC.
> 
> Yes.  I found the entry in the application log.  I checked the old XP
> box
> where ntp works well and that's using the MM timer.
> 
> > This is always my sign that ntpd offset will diverge, and requires a
> > system restart, or more.
> 
> > Also when leap=11 that is the alarm state that says there are issues.
> 
> Does leap=11 mean the server is not sync'd?
> 
> > Wait until reach is 377 on all sources and check again for leap=00.
> 
> I removed the -M from the service executable command and rebooted.
> 
> After 15 minutes I got this
> 
> C:\Users\nick>ntpq -pn
>      remote           refid      st t when poll reach   delay   offset
> jitter
> =======================================================================
> =======
> -143.210.16.201  158.43.192.66    2 u   33   64  377   32.491  181.643
> 121.179
> +85.119.80.233   110.116.250.33   3 u   29   64  377   29.461   59.626
> 88.079
> +176.74.25.228   193.47.164.28    3 u   21   64  377   30.159   91.825
> 72.384
> +176.74.25.227   193.11.166.8     2 u   32   64  377   30.065   20.692
> 117.706
> +5.39.184.5      87.195.109.207   3 u   26   64  377   37.018   -3.686
> 138.898
>  94.228.220.14   .INIT.          16 u    -   64    0    0.000    0.000
> 0.000
> *130.88.212.143  193.62.22.90     2 u   36   64  377   37.078   62.566
> 93.284
> 
> C:\Users\nick>ntpq -c rv
> associd=0 status=0615 leap_none, sync_ntp, 1 event, clock_sync,
> version="ntpd 4.2.7p450 at 1.2483-o Jul 17 7:20:46.78 (UTC+01:00) 2014
> (1)",
> processor="x86", system="Windows", leap=00, stratum=3, precision=-22,
> rootdelay=46.020, rootdisp=139.381, refid=130.88.212.143,
> reftime=d773f6dd.29fb24ea  Fri, Jul 18 2014 20:41:17.163,
> clock=d773f753.cf14ee36  Fri, Jul 18 2014 20:43:15.808, peer=40459,
> tc=6,
> mintc=3, offset=67.250982, frequency=431.145, sys_jitter=54.722048,
> clk_jitter=36.149, clk_wander=0.139
> 
> ntp.conf...
> 
> restrict default nomodify notrap nopeer noquery
> restrict 127.0.0.1
> restrict -6 ::1
> driftfile "C:\Tools (x86)\NTP\etc\ntp.drift"
> server 0.uk.pool.ntp.org iburst  minpoll 6 maxpoll 6
> server 1.uk.pool.ntp.org iburst minpoll 6 maxpoll 6
> server 2.uk.pool.ntp.org iburst minpoll 6 maxpoll 6
> server 3.uk.pool.ntp.org iburst minpoll 6 maxpoll 6
> server 0.nl.pool.ntp.org iburst minpoll 6 maxpoll 6
> server 1.nl.pool.ntp.org iburst minpoll 6 maxpoll 6
> server ntp2d.mcc.ac.uk iburst minpoll 6 maxpoll 6
> enable stats
> statsdir "C:\Tools (x86)\NTP\etc\"
> statistics loopstats
> 
> It's working! So the MM timer seems to mess up ntp on Win 7 but not on
> XP.
> 
> This performance is marginal for WSJTX.  I need 10ms offset or less
> after
> 15 minutes.
> 
> I would like to have used the pool directive in ntp.conf but the
> development versions don't seem to process it.  (The Meinberg monitor
> says unknown clock type.)
> 
> To put it in perspective here's the performance I get on the same
> machine
> when I boot Mint 17.
> 
> nick at mint17-01 ~ $ ntpq -pn
>      remote           refid      st t when poll reach   delay   offset
> jitter
> =======================================================================
> =======
> -129.250.35.251  192.93.2.20      2 u   50   64  377   37.766   -0.413
> 22.384
> +176.58.109.199  131.188.3.223    2 u   51   64  377   29.532    3.113
> 1.482
> *178.79.160.57   130.133.1.10     2 u   48   64  377   29.074    2.984
> 1.994
> -87.117.251.3    129.215.160.240  3 u   46   64  377   29.621    1.225
> 1.466
> +130.88.212.143  193.62.22.90     2 u   42   64  377   37.233    1.904
> 1.187
> 
> nick at mint17-01 ~ $ ntpq -c rv associd=0
> status=0615 leap_none, sync_ntp, 1 event, clock_sync,
> version="ntpd 4.2.6p5 at 1.2349-o Wed Oct  9 19:08:06 UTC 2013 (1)",
> processor="x86_64", system="Linux/3.13.0-24-generic", leap=00,
> stratum=3,
> precision=-23, rootdelay=31.652, rootdisp=59.450, refid=85.234.136.65,
> reftime=d773f099.353d9b27  Fri, Jul 18 2014 20:14:33.207,
> clock=d773f2b2.69839d3d  Fri, Jul 18 2014 20:23:30.412, peer=14600,
> tc=6,
> mintc=3, offset=1.095, frequency=-20.457, sys_jitter=1.518,
> clk_jitter=0.703, clk_wander=0.101
> 
> This uses pool pool.uk.ntp.org and server ntp2d.mcc.ac.uk.
> 
> Is it possible to ever get the same level of performance on Windows 7?
> 
> _______________________________________________
> questions mailing list
> questions at lists.ntp.org
> http://lists.ntp.org/listinfo/questions



More information about the questions mailing list