PHP-FPM主进程CPU负载异常升高问题排查求助

我们运行的是PHP 8.2.27版本的FPM 8，配置如下：

pm = dynamic
pm.max_children = 500
pm.start_severs = 32
pm.min_spare_servers = 32
pm.max_spare_servers = 64
pm.max_requests = 1000

初始启动时FPM运行平稳，但随时间推移，即便子进程数量变化不大，主进程CPU占用仍持续上升。未出现脚本挂起情况，直到主进程CPU占用达到阈值后问题爆发：当主进程单核心CPU占用超过90%（约占总核心的24%）时，主进程频繁启停，FPM持续创建并销毁无实际用途的子进程，最终导致崩溃或挂起。日志仅记录FPM无法写入stdout。

以下是FPM挂起前monit的监控数据：

Process 'php-fpm8'

status                       OK
monitoring status            Monitored
monitoring mode              active
on reboot                    start
pid                          2977861
parent pid                   1
uid                          0
effective uid                0
gid                          0
uptime                       1d 0h 9m
threads                      1
children                     50
cpu                          98.4%
cpu total                    98.9%
memory                       0.8% [375.9 MB]
memory total                 25.5% [11.9 GB]
security attribute           kernel
filedescriptors              69 [6.7% of 1024 limit]
total filedescriptors        351
read bytes                   21.2 kB/s [601.1 GB total]
disk read bytes              0 B/s [19.2 GB total]
disk read operations         55.3 reads/s [175652524 reads total]
write bytes                  0 B/s [53.3 GB total]
disk write bytes             0 B/s [915.9 MB total]
disk write operations        5.0 writes/s [14306972 writes total]
data collected               Fri, 07 Mar 2025 09:32:53

内容的提问来源于stack exchange，提问作者Lukas Reeves