Integrated: 8255737: Zero: DO_UPDATE_INSTRUCTION_COUNT should only update when relevant VM flags are set

[Aleksey Shipilev]

On Mon, 2 Nov 2020 08:58:56 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Everywhere else in VM code we effectively do:
> 
>   if (CountBytecodes || TraceBytecodes || StopInterpreterAt) BytecodeCounter::...
>   if (PrintBytecodeHistogram) BytecodeHistogram::...
> 
> But not in `DO_UPDATE_INSTRUCTION_COUNT` macro.
> Adding these flags avoid the writes to statistics what would never be used (and those writes can even contend, afaics).
> This change drops the Linux x86_64 Zero fastdebug build time from ~18m to ~17.5m.
> 
> Testing:
>  - [x] Ad-hoc runs with Zero and affected flags

This pull request has now been integrated.

Changeset: f389a718
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/f389a718
Stats:     17 lines in 1 file changed: 6 ins; 0 del; 11 mod

8255737: Zero: DO_UPDATE_INSTRUCTION_COUNT should only update when relevant VM flags are set

Reviewed-by: sgehwolf

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PR: https://git.openjdk.java.net/jdk/pull/997