[ntp:questions] .1 Microsecond Synchronization

Unruh unruh-spam at physics.ubc.ca
Thu Jun 4 20:58:20 UTC 2009

E-Mail Sent to this address will be added to the BlackLists <Null at BlackList.Anitech-Systems.invalid> writes:

>Unruh wrote:
>>> The company I am working for needs to be able to record
>>>  timestamps in a trading system logs down to a .1
>>>  microsecond accuracy.

>>> We will have servers located in London, New York and Chicago.
>>> There will be a dedicated resilient link between London
>>>  and New York.

>> Maybe if you are willing to throw 10 million at it,
>>  you MIGHT be able to get there.

>NTP running with a cesium clock and a GPS PPS receiver,
> in every machine that need to do the time stamping?

Nope, you somehow have to get the operating system to query the clock
within .1usec, and transfer that time base to the trade loging system
within better than .1usec, which means no interrupts can have occured
during that time, and the trade has to have somehow been brought into
the computer on a timescale better than that (that is 10 characters on a
GB ethernet and the opposite end of that ethernet better be less than 
30m away with no switches between you and the other end. Ie, this
requirement is absurd.  And of course that trade was typed in by a
trader with hunt and peck keyboard skills which means his entry of the
trade had an accuracy of 10 sec, if you are very lucky. 

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