RFR: 8284849: Add deoptimization to unified logging [v6]

[Vladimir Kozlov]

On Wed, 8 Jun 2022 12:57:56 GMT, Johan Sjölén <duke at openjdk.java.net> wrote:

>> This PR adds a new "deoptimization" tag and a new log message on the info level mimicking JFR's deoptimization event. In the future this tag will be used to add trace level information, hopefully replacing TraceDeoptimization. JFR's event also captures the stacktrace, which this does not (happy to add this if considered important).
>> 
>> An example output looks like this: 
>> 
>> 
>> [1.346s][info][deoptimization] Deoptimization start {
>> [1.346s][info][deoptimization]   compileId = 407
>> [1.346s][info][deoptimization]   compiler = c2
>> [1.346s][info][deoptimization]   method:lineno:bci = java.util.concurrent.locks.ReentrantLock$Sync.tryRelease(I)Z:176:26
>> [1.346s][info][deoptimization]   instruction = ifne
>> [1.346s][info][deoptimization]   reason = unstable_if
>> [1.346s][info][deoptimization]   action = reinterpret
>> [1.346s][info][deoptimization] } Deoptimization end
>
> Johan Sjölén has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Simplify code
>  - Refactor using LogStream

Few more comments.

src/hotspot/share/runtime/deoptimization.cpp line 1849:

> 1847:     ls.print("cid=%d %s pc=" INTPTR_FORMAT " relative_pc=" INTPTR_FORMAT " level=%d",
> 1848:              nm->compile_id(), (is_osr ? "%" : ""), pc, fr.pc() - nm->code_begin(),
> 1849:              nm->comp_level());

Please, print `pc` and `relative_pc` at the end of output.
I may be was not clear but do not use `%` for OSR marking. Please use your pattern to make it clear because you have other `bci`: `osr_bci=%d`

src/hotspot/share/runtime/deoptimization.cpp line 1852:

> 1850:     nm->method()->print_short_name(&ls);
> 1851:     ls.print(" @ ");
> 1852:     ls.print("%d ", trap_bci);

Instead of `@ %d` please use same pattern: `trap_bci=%d`.

src/hotspot/share/runtime/deoptimization.cpp line 1965:

> 1963:       Events::log_deopt_message(current, "Uncommon trap: reason=%s action=%s pc=" INTPTR_FORMAT " method=%s @ %d %s",
> 1964:                                 reason_name, reason_action, pc,
> 1965:                                 tm->name_and_sig_as_C_string(), trap_bci, nm->compiler_name());

I actually thought about putting all these logging (JFR, UL, Event) into separate method. But this looks fine as well - keep it.

src/hotspot/share/runtime/deoptimization.hpp line 172:

> 170: 
> 171:     // Does the actual work for deoptimizing a single frame
> 172:     static void deoptimize_single_frame(JavaThread* thread, frame fr, DeoptReason reason);

Please, keep original indent for this lines to match other line around. Actually `private:` has wrong additional space.

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PR: https://git.openjdk.java.net/jdk/pull/8812