On Sat, 24 May 2025 17:48:16 GMT, Markus Grönlund <mgron...@openjdk.org> wrote:
>> src/hotspot/share/jfr/support/jfrThreadLocal.hpp line 103:
>>
>>> 101: volatile CPUTimeLockState _cpu_time_jfr_locked = UNLOCKED;
>>> 102: volatile bool _has_cpu_time_jfr_requests = false;
>>> 103: JfrCPUTimeTraceQueue _cpu_time_jfr_queue{0};
>>
>> Please initialize these fields in the initializer list, like the other
>> fields.
>>
>> Also, what capacity will the JfrCPUTimeTraceQueue have with an initializer
>> like the above - {0}? In GDB i see that the capacity is 10000. Each element
>> is 48 bytes, meaning each thread now has an associated queue of 468 kb,
>> almost 0.5 Mb. Is that correct?
>
> I see that JfrCPUTimeTraceQueue::ensure_capacity_for_period() calculates and
> sets the queue size as a function of the sampling period (in my case its 1
> ms).
I reduced the base capacity to 500, but with far smaller values we risk many
more lossed events. We should probably tune this value at the end.
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PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2106782239
