[HACKERS] How to do fast performance timing

2013-12-09 Thread Benedikt Grundmann 
At Jane Street we have recently spend a lot of time trying to get a fast
gettimeofday.  I saw lots of references in various postgres hacker threads
related to a lack of such a facility so 

The culmination of those efforts can be read here:

https://github.com/janestreet/core/blob/master/lib/time_stamp_counter.mli
and

https://github.com/janestreet/core/blob/master/lib/time_stamp_counter.ml

it's all OCaml but the code is mostly imperative and very well documented.
In particular we made an effort to document our assumption.  There are a
few which are ocaml specific.  But a lot of the lessons we have learned
here should be applicable to postgres.

Hope this will be useful,

Cheers,

Bene

PS: We are releasing our code under the Apache license so you should feel
free to reuse the ideas.

Re: [HACKERS] How to do fast performance timing

2013-12-09 Thread Jim Nasby 

On 12/9/13 7:33 AM, Benedikt Grundmann wrote:

At Jane Street we have recently spend a lot of time trying to get a fast 
gettimeofday.  I saw lots of references in various postgres hacker threads 
related to a lack of such a facility so 

The culmination of those efforts can be read here:

https://github.com/janestreet/core/blob/master/lib/time_stamp_counter.mli
and

https://github.com/janestreet/core/blob/master/lib/time_stamp_counter.ml

it's all OCaml but the code is mostly imperative and very well documented.  In 
particular we made an effort to document our assumption.  There are a few which 
are ocaml specific.  But a lot of the lessons we have learned here should be 
applicable to postgres.


Looks interesting. I think this isn't nearly as big an issue in Postgres as it 
used to be, but I think there's also things we've been avoiding because of the 
overhead. IE: using IO response time to determine if something came from cache 
or not.
--
Jim C. Nasby, Data Architect   j...@nasby.net
512.569.9461 (cell) http://jim.nasby.net


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