[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?
>
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