RFR(S, tedious): 8217250: Optimize CodeHeap Analytics

[Schmidt, Lutz]

Thank you, Tobias!

As this enhancement will not make it into jdk12, I'll rebase it to jdk/jdk. I expect no conflicts and assume I can then push without further webrev/review. 

Thanks,
Lutz

On 18.01.19, 10:49, "Tobias Hartmann" <tobias.hartmann at oracle.com> wrote:

    Hi Lutz,
    
    looks good to me too.
    
    Best regards,
    Tobias
    
    On 17.01.19 19:39, Vladimir Kozlov wrote:
    > Looks good
    > 
    > Thanks,
    > Vladimir
    > 
    > On 1/17/19 7:47 AM, Schmidt, Lutz wrote:
    >> Hi Vladimir & all,
    >> there is a new webrev available: http://cr.openjdk.java.net/~lucy/webrevs/8217250.01/
    >> What's new (in addition to some comments) is the macro
    >>
    >>    // Flush the buffer contents if the remaining capacity is less
    >>    // than the calculated threshold (256 bytes + capacity/16)
    >>    // That should suffice for all reasonably sized output lines.
    >>    #define BUFFEREDSTREAM_FLUSH_AUTO(_termString)                \
    >>        BUFFEREDSTREAM_FLUSH_IF(_termString, 256+(_capacity>>4))
    >>
    >> It replaced the previous BUFFEREDSTREAM_FLUSH_IF("string", 512) occurrences.
    >> Regards,
    >> Lutz
    >>
    >> On 16.01.19, 22:53, "Vladimir Kozlov" <vladimir.kozlov at oracle.com> wrote:
    >>
    >>      On 1/16/19 12:37 PM, Schmidt, Lutz wrote:
    >>      > Hi Vladimir,
    >>      >
    >>      > thanks a lot for looking at this so quickly.
    >>      >
    >>      > Sure, I could declare a specialized "BUFFEREDSTREAM_FLUSH_512" for this. The "512"
    >> originated from the thought "its large enough for a well-behaved line and small enough to save
    >> some flushes".
    >>      >
    >>      > I was also thinking about a "BUFFEREDSTREAM_FLUSH_AUTO", where the spare space is derived
    >> from the buffer capacity, maybe something like 10 percent of the capacity, 256 bytes minimum. I
    >> wasn't sure if that could be categorized as over-engineered.
    >>           Yes, I think BUFFEREDSTREAM_FLUSH_AUTO is better than fixed size.
    >>           Vladimir
    >>           >
    >>      > Your thoughts?
    >>      >
    >>      > Thanks,
    >>      > Lutz
    >>      >
    >>      > On 16.01.19, 19:10, "hotspot-compiler-dev on behalf of Vladimir Kozlov"
    >> <hotspot-compiler-dev-bounces at openjdk.java.net on behalf of vladimir.kozlov at oracle.com> wrote:
    >>      >
    >>      >      Hi Lutz,
    >>      >
    >>      >      I see that you have only one usage in all cases for:
    >>      >      BUFFEREDSTREAM_FLUSH_IF("", 512)
    >>      >
    >>      >      Can you simple declare simplified macro for this?
    >>      >
    >>      >      Otherwise looks good.
    >>      >
    >>      >      Thanks,
    >>      >      Vladimir
    >>      >
    >>      >      On 1/16/19 6:52 AM, Schmidt, Lutz wrote:
    >>      >      > Dear all,
    >>      >      >
    >>      >      > may I please have reviews for this (semantically) small change. Its purpose is to
    >> reduce the bufferedStream buffer flushes while printing CodeHeap Analytics.
    >>      >      >
    >>      >      > Bug:    https://bugs.openjdk.java.net/browse/JDK-8217250
    >>      >      > Webrev: http://cr.openjdk.java.net/~lucy/webrevs/8217250.00/
    >>      >      >
    >>      >      > Thank you!
    >>      >      > Lutz
    >>      >      >
    >>      >      >
    >>      >
    >>      >
    >>