RFR[9u-dev]: 8054326: Confusing message in "Current rem set statistics"

Cheleswer Sahu cheleswer.sahu at oracle.com
Mon Apr 11 13:33:21 UTC 2016


Hi,


-----Original Message-----
From: Per Liden 
Sent: Friday, April 08, 2016 1:57 PM
To: Mikael Gerdin; Cheleswer Sahu; hotspot-gc-dev at openjdk.java.net
Subject: Re: RFR[9u-dev]: 8054326: Confusing message in "Current rem set statistics"

Hi,

On 2016-04-06 13:09, Mikael Gerdin wrote:
[...]
>> Hi,
>>
>>
>> Please review the code changes for
>> https://bugs.openjdk.java.net/browse/JDK-8054326.
>>
>>
>> Webrev Link: http://cr.openjdk.java.net/~csahu/8054326/
>>

We try to avoid printing sizes with dynamically selected binary prefixes
(K/M/G) for the simple reason that it makes it harder to grep through and compare GC logs. If that "rule" applies here can be discussed.

We already have the functions
proper_unit_for_byte_size/byte_size_in_proper_unit to do roughly what you've done, but they are very rarely used for the reason stated above.

Mikael had directed me towards this function when we had offline chat regarding this, but this function prints in KB only if size is  greater than 10k. Therefore I had written my own code to print this.  

There are a other places in this code/function where we're also printing potentially small values as K, which you haven't addressed here. Just addressing one of the places seems like an incomplete fix.

Yes, I agree there are other places too which can be considered. I just took the "Max" part because I was not sure about others.

I'm personally not sure if this is a problem big enough to worth addressing at all. Maybe others have a different opinion, Thomas/Bengt/Mikeal/Stefan?

Does any have any other opinion regarding this ? We in sustaining team although feel that showing "Max" as 0k is ambiguous.


Regards,
Cheleswer
cheers,
Per

>>
>> Bug Brief: In output of remset statistics "Max"  is printing as 0k, 
>> which is confusing for user.
>>
>>
>>
>> Problem Identified : "Max" value is rounded to KB, which result  in 
>> 0k, if the value is less than 1024B.
>>
>>
>>
>> Solution Proposed:  If the value for "Max" is less than 1 KB (1024 
>> B),  print the value in bytes (i.e. 1023B.) else
>>
>> print the value in KB.
>>
>>
>>
>>
>>
>>
>>
>> Regards,
>>
>> Cheleswer
>>
>>
>>


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