Discussion about logging *Basic* statistic of evacuation failure

[Thomas Schatzl]

Hi,

On 06.12.21 08:25, lihuaming (A) wrote:
> Hi all,
> 
> May I have your attention to discuss about logging *Basic* statistic of 
> evacuation failure, this is to get more information about the pause time 
> distribution and region/objects/size statistics when processing 
> evacuation failure objects in “Remove Self Forwards”, this information 
> will be helpful when optimize the evacuation failure processing 
> subsequently, and will also be helpful for users to analyze and 
> troubleshoot in the future.
> 
> Below are the basic statistics to be logged, would you mind to share 
> your points about this logging message?
> 
> ```
> 
>  Remove Self Forwards Total (ms): 

I would like to step away from the term "Evacuation Failure" in the log 
messages - we will be using this mechanism for pinned region as well and 
I'm not really sure that using a term with "failure" in the name for 
something that is a regular non-exceptional occurrence.

"Remove Self Forwards" is fine.

Here are some suggestions for the log messages:

In-Place Evacuation (ms)        // Not sure if this is an "evacuation"
                                 // but "In-Place" Handling isn't really
                                 // good.
   In-Place Regions              // Maybe these three could be reported
                                 // in "Object Copy"? But is fine here
   Self Forwarded Objects        // too.
   In-Place Live Bytes

"In-Place Regions" might be split later in "Pinned regions" and 
"Evacuation Failed Regions" (which we might use instead of "In-Place 
Regions" already).

Would be nice to have "Memory Usage" for the segments/allocators too 
here somewhere.

As for the sub-phases I prefer more specific terms to generic ones like 
"prepare", "process", "cleanup".

   Sort Self Forward Refs (ms)   // Also not that good probably :)
   Remove Self Forwards (ms)     // Actual work
   Reclaim Memory (ms)

But probably others have better ideas :) I will continue thinking about 
this.

Just my initial 2 cents,
   Thomas