问题：

我昨晚把Ubuntu 20.04升级了，并保留了相同的mysql conf文件，现在同一个应用程序需要45-47秒！

6.27user 0.41system 1:45.53elapsed 6%CPU (0avgtext+0avgdata 168724maxresident)k


0inputs+384outputs (0major+42056minor)pagefaults 0swaps

我尝试将"acpi ht"添加到/etc/default/grub，并重新启动计算机，以关闭电源管理，但处理器仍在低频运行，并且可能无法提高频率。

On-line CPU(s) list: 0-15


Thread(s) per core: 2


Core(s) per socket: 4


Socket(s): 2


NUMA node(s): 2


Vendor ID: GenuineIntel


CPU family: 6


Model: 44


Model name: Intel(R) Xeon(R) CPU E5620 @ 2.40GHz


Stepping: 2


Frequency boost: enabled


CPU MHz: 1599.592


CPU max MHz: 2401.0000


CPU min MHz: 1600.0000


BogoMIPS: 4799.75


Virtualization: VT-x


L1d cache: 256 KiB


L1i cache: 256 KiB


L2 cache: 2 MiB


L3 cache: 24 MiB

-------- InnoDB Metrics ----------------------------------------------------------------------------


[--] InnoDB is enabled.


[--] InnoDB Thread Concurrency: 8


[OK] InnoDB File per table is activated


[OK] InnoDB buffer pool / data size: 9.0G/2.6G


[OK] Ratio InnoDB log file size / InnoDB Buffer pool size: 1.0G * 2/9.0G should be equal 25%


[OK] InnoDB buffer pool instances: 9


[--] Number of InnoDB Buffer Pool Chunk : 72 for 9 Buffer Pool Instance(s)


[OK] Innodb_buffer_pool_size aligned with Innodb_buffer_pool_chunk_size & Innodb_buffer_pool_instances


[OK] InnoDB Read buffer efficiency: 99.90% (2901594 hits/ 2904524 total)


[!!] InnoDB Write Log efficiency: 75.47% (19033 hits/ 25219 total)


[OK] InnoDB log waits: 0.00% (0 waits / 6186 writes)

显示Java只在启动时使用< 1-的cpu使用量。

 2113 mysql 20 0 25.7g 2.7g 36264 S 4.3 11.6 0:12.35 mysqld


 353 root 20 0 0 0 0 S 2.7 0.0 0:02.99 md0_raid5


 244 root 0 -20 0 0 0 I 0.7 0.0 0:00.98 kworker/10:1H-kblockd


 248 root 0 -20 0 0 0 I 0.7 0.0 0:00.07 kworker/8:1H-kblockd


 399 root 20 0 0 0 0 D 0.7 0.0 0:00.61 jbd2/md0-8


 2372 bias 20 0 5597164 180592 27784 S 0.7 0.7 0:07.54 java

 4654 user 20 0 3856 100 0 R 100.0 0.0 0:13.88 stress


 4643 user 20 0 3856 100 0 R 100.0 0.0 0:13.82 stress


 4645 user 20 0 134932 3272 272 R 100.0 0.0 0:13.84 stress


 4646 user 20 0 3856 100 0 R 100.0 0.0 0:13.80 stress

答案1：

更新操作系统时，MySQL JDBC驱动程序的默认行为显然已更改。

https://coderanch.com/t/299833/databases/Batch-update-setAutoCommit-false