Re: [Ntp] Antw: Re: Antw: [EXT] Minutes from IETF 108 NTP WG session
Miroslav Lichvar <mlichvar@redhat.com> Mon, 03 August 2020 11:21 UTC
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Date: Mon, 03 Aug 2020 13:21:30 +0200
From: Miroslav Lichvar <mlichvar@redhat.com>
To: Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>
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Subject: Re: [Ntp] Antw: Re: Antw: [EXT] Minutes from IETF 108 NTP WG session
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On Mon, Aug 03, 2020 at 01:01:02PM +0200, Ulrich Windl wrote: > On one machine I got these debugging messages: > (D)get_res: resolution is 0.000000001 ## from POSIX call > (D)get_res: smallest delta is 0.000001514 > (D)get_res: largest delta is 0.000001695 > (I)set_resolution: ts 0.000001514, digits 6, nsecs 1000 This suggests the system is not using the TSC clocksource, but something slower like HPET. Check the following files: /sys/devices/system/clocksource/clocksource0/current_clocksource /sys/devices/system/clocksource/clocksource0/available_clocksource > So your machines must be way faster... OK, I tried the latest generation we > have: No, they are not faster, just using the TSC clocksource. On some machines it's unreliable, so the kernel may need to switch to a slower clocksource. IIRC even the first Intel Core and AMD Athlon 64 CPUs from the 2000s were about 50ns or better. Make sure the CPU is running at full speed (e.g. disabled ondemand governor). -- Miroslav Lichvar
- [Ntp] Minutes from IETF 108 NTP WG session Dieter Sibold
- [Ntp] Antw: [EXT] Minutes from IETF 108 NTP WG se… Ulrich Windl
- Re: [Ntp] Antw: [EXT] Minutes from IETF 108 NTP W… Miroslav Lichvar
- [Ntp] Antw: Re: Antw: [EXT] Minutes from IETF 108… Ulrich Windl
- Re: [Ntp] Antw: Re: Antw: [EXT] Minutes from IETF… Miroslav Lichvar
- Re: [Ntp] Antw: Re: Antw: [EXT] Minutes from IETF… Hal Murray
- Re: [Ntp] Antw: Re: Antw: [EXT] Minutes from IETF… Hal Murray
- Re: [Ntp] Antw: Re: Antw: [EXT] Minutes from IETF… Miroslav Lichvar