On 08.09.15 11:35, Savolainen, Petri (Nokia - FI/Espoo) wrote:


-----Original Message-----
From: ext Ivan Khoronzhuk [mailto:ivan.khoronz...@linaro.org]
Sent: Tuesday, September 08, 2015 10:26 AM
To: Savolainen, Petri (Nokia - FI/Espoo); lng-odp@lists.linaro.org
Subject: Re: [lng-odp] [API-NEXT PATCH 3/5] linux-generic: cpu: rename
time_cycles to cpu_cycles



On 07.09.15 15:41, Petri Savolainen wrote:
Implemented odp_cpu_cycles() be renaming odp_time_cycles()
implementation. Time implementation uses odp_cpu_cycles
temporarely.

Right. You didn't add functional changes here.
Currently It's not documented that odp_time_cycles returns global
cycles ).
But time API does. So question is, on what I should replace this
function for
linux generic. on clock_gettime ? Which impact it will have on
applications/tests/examples?
Do we have choice?

This series does not change time API or functionality of the implementation,
just adds CPU cycles API. The new time API needs to specify global wall clock 
time
 and implement it so that it's globally synchronized (==> not use CPU cycles 
counter
any more, if those counters are not kept in sync by the HW)
+, or can be impacted by freq change.

I'm afraid that it will be smth similar to timer API s/w counter.
Which has not very good resolution for short time measurements.
Do we have direct access to counters in linux-generic cases, like it's done for 
cycles?


-Petri


--
Regards,
Ivan Khoronzhuk
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