[PATCH 3/3] Decompress the CRBB bitmap using tree based approach

Holger Freyther holger at freyther.de
Thu Mar 31 11:25:10 UTC 2016


> On 31 Mar 2016, at 13:04, Max <msuraev at sysmocom.de> wrote:
> 
> Hi and thanks for detailed write-up.
> 
> So the code do exactly the same thing just more efficiently under the
> assumption that gcc optimization is not working.
> Is there a way to quantify this potential difference?

Hi Sangamesh,

let me refer to Haralds mail on optmization and let me add that any "performance" improvement needs to have a benchmark that proves progress.

Looking at both implementations I am not convinced any of the two will be faster/slower than the other. Now the look-up in a tree might be log(N) in terms of compares but as each tree node is sitting on different memory (between we never use malloc, but always use talloc to allocate) the cache misses might make it slower than Max's version.

Please collect typical bitmaps, create a benchmark and compare the two implementations and we can make a decision.

thank you
	holger





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