RFR(trivial): 8231024: Improve the debug info when the output is truncated

[Jie Fu]

Good catch, Ioi.
Will update the patch soon.
Thank you very much.

On 2019/9/15 上午5:45, Ioi Lam wrote:
> Hi Jie,
>
> I think this is a good idea, but the printed value is off by one when 
> add_cr is true.
>
> Thanks
> - Ioi
>
> On 9/14/19 2:00 AM, Jie Fu wrote:
>> Hi all,
>>
>> JBS:    https://bugs.openjdk.java.net/browse/JDK-8231024
>> Webrev: http://cr.openjdk.java.net/~jiefu/8231024/webrev.00/
>>
>> *Background*
>> When I was running a jtreg test with
>> ------------------------------------
>> make test 
>> TEST="test/jdk/java/lang/invoke/TestCatchExceptionWithVarargs.java" 
>> CONF=fast
>> ------------------------------------
>> I got some VM warnings which just told me to increase O_BUFLEN in 
>> ostream.hpp.
>> But the debug info didn't tell us the proper value of O_BUFLEN needed 
>> by the output.
>>
>> It might be better to dump the required value of O_BUFLEN.
>>
>> *Fix*
>>
>> - Before the patch
>> ------------------------------------
>> [2019-09-14 16:07:55,752] Agent[1]: stderr: OpenJDK 64-Bit Server VM 
>> warning: increase O_BUFLEN in ostream.hpp -- output truncated
>> [2019-09-14 16:07:55,758] Agent[1]: stderr: OpenJDK 64-Bit Server VM 
>> warning: increase O_BUFLEN in ostream.hpp -- output truncated
>> [2019-09-14 16:07:55,763] Agent[1]: stderr: OpenJDK 64-Bit Server VM 
>> warning: increase O_BUFLEN in ostream.hpp -- output truncated
>> ...
>> ------------------------------------
>>
>> - After the patch
>> ------------------------------------
>> [2019-09-14 16:19:09,478] Agent[1]: stderr: OpenJDK 64-Bit Server VM 
>> warning: increase O_BUFLEN in ostream.hpp: at least 2013 is required 
>> -- output truncated
>> [2019-09-14 16:19:09,482] Agent[1]: stderr: OpenJDK 64-Bit Server VM 
>> warning: increase O_BUFLEN in ostream.hpp: at least 2031 is required 
>> -- output truncated
>> [2019-09-14 16:19:09,488] Agent[1]: stderr: OpenJDK 64-Bit Server VM 
>> warning: increase O_BUFLEN in ostream.hpp: at least 2049 is required 
>> -- output truncated
>> ------------------------------------
>>
>> Could you please review it?
>>
>> Thanks a lot.
>> Best regards,
>> Jie
>>
>>
>