jdk11g1gc花费大量时间准备TLAB
gc.log显示Prepare TLABs阶段花费了大约 57 秒，这是不可接受的。而且，这种情况五天才发生一次。我只想弄清楚究竟发生了什么以及如何避免。
[gc.log]
[2021-08-02T11:38:38.134+0800][322490.377s][161325][safepoint ] Entering safepoint region: G1CollectForAllocation
[2021-08-02T11:38:38.134+0800][322490.378s][161325][gc,start ] GC(238) Pause Young (Normal) (G1 Evacuation Pause)
[2021-08-02T11:38:38.134+0800][322490.378s][161325][gc,task ] GC(238) Using 18 workers of 18 for evacuation
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Pre Evacuate Collection Set: 0.1ms
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Prepare TLABs: 57039.1ms
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Choose Collection Set: 0.0ms
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Humongous Register: 0.1ms
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Evacuate Collection Set: 3.8ms
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Ext Root Scanning (ms): Min: 0.0, Avg: 0.4, Max: 3.5, Diff: 3.5, Sum: 7.2, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Update RS (ms): Min: 0.0, Avg: 0.5, Max: 0.9, Diff: 0.9, Sum: 8.7, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Processed Buffers: Min: 0, Avg: 2.9, Max: 16, Diff: 16, Sum: 53, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Scanned Cards: Min: 0, Avg: 265.7, Max: 623, Diff: 623, Sum: 4783, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Skipped Cards: Min: 0, Avg: 20.4, Max: 32, Diff: 32, Sum: 368, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Scan RS (ms): Min: 0.0, Avg: 0.2, Max: 0.3, Diff: 0.3, Sum: 3.2, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Scanned Cards: Min: 0, Avg: 27.3, Max: 120, Diff: 120, Sum: 491, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Claimed Cards: Min: 0, Avg: 29.9, Max: 129, Diff: 129, Sum: 538, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Skipped Cards: Min: 0, Avg: 187.6, Max: 347, Diff: 347, Sum: 3377, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) AOT Root Scanning (ms): skipped
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Object Copy (ms): Min: 0.0, Avg: 2.0, Max: 2.6, Diff: 2.6, Sum: 35.7, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.422s][161325][gc,phases ] GC(238) Termination (ms): Min: 0.0, Avg: 0.4, Max: 0.6, Diff: 0.6, Sum: 7.4, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Termination Attempts: Min: 1, Avg: 4.8, Max: 9, Diff: 8, Sum: 86, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) GC Worker Other (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.2, Sum: 2.2, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) GC Worker Total (ms): Min: 3.4, Avg: 3.6, Max: 3.7, Diff: 0.3, Sum: 64.7, Workers: 18
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Post Evacuate Collection Set: 1.0ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Code Roots Fixup: 0.0ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Clear Card Table: 0.2ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Reference Processing: 0.1ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Weak Processing: 0.1ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Merge Per-Thread State: 0.1ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Code Roots Purge: 0.0ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Redirty Cards: 0.1ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) DerivedPointerTable Update: 0.0ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Free Collection Set: 0.3ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Humongous Reclaim: 0.1ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Start New Collection Set: 0.0ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Resize TLABs: 0.0ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Expand Heap After Collection: 0.0ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,phases ] GC(238) Other: 57039.6ms
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,heap ] GC(238) Eden regions: 865->0(867)
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,heap ] GC(238) Survivor regions: 27->25(112)
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,heap ] GC(238) Old regions: 20->20
[2021-08-02T11:39:35.179+0800][322547.423s][161325][gc,heap ] GC(238) Humongous regions: 5->5
[2021-08-02T11:39:35.180+0800][322547.423s][161325][gc,metaspace ] GC(238) Metaspace: 45664K->45664K(1091584K)
[2021-08-02T11:39:35.180+0800][322547.423s][161325][gc ] GC(238) Pause Young (Normal) (G1 Evacuation Pause) 916M->48M(1488M) 57045.332ms
[2021-08-02T11:39:35.180+0800][322547.423s][161325][gc,cpu ] GC(238) User=0.00s Sys=0.09s Real=57.05s
[2021-08-02T11:39:35.180+0800][322547.423s][161325][safepoint ] Leaving safepoint region
[2021-08-02T11:39:35.180+0800][322547.423s][161325][safepoint ] Total time for which application threads were stopped: 57.0457609 seconds, Stopping threads took: 0.0000407 seconds