RFR: 8346264: "Total compile time" counter should include time spent in failing/bailout compiles [v2]

[Vladimir Kozlov]

On Mon, 16 Dec 2024 11:25:50 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Noticed this when looking through JMH compiler profiler results.
>> 
>> Current `CompilerBroker` counters that are fed into `CompilationMXBean.getTotalCompilationTime()` and JFR `CompilerStatistics` only records the time for successful compilations. If we take a while in compilation and then fail/bail, that time would not be accounted for.
>> 
>> While this seems to be a long-standing behavior, there are problems with this:
>>  1. This is not what "total" means.
>>  2. This gives us a blind spot in measuring time taken in failing/bailing compilations.
>>  3. It does not match well the Javadoc for `CompilationMXBean.getTotalCompilationTime()`: "Returns the approximate accumulated elapsed time (in milliseconds) spent in compilation." -- since the time spent in failing/bailing compilation is still time spent in compilation.
>> 
>> Additional testing:
>>  - [x] Linux x86_64 server release, `jdk/jfr java/lang/management`
>
> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update comment

Would be nice to add separate time for failed/bailout compilations to get sense how much time we spend in them.

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PR Review: https://git.openjdk.org/jdk/pull/22760#pullrequestreview-2507017038