PostgreSQL通过参数huge_pages设置是否启用大页，利用常驻内存用以提升性能，本节简单介绍了Linux中Huge Pages的相关设置。 *Check if CPU supports HugePages 2MB Size* 命令如下，关键字是*pse(Page Size Extension)* ``` [root@localhost ~]# cat /proc/cpuinfo | grep pse | uniq flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm fsgsbase smep arat [root@localhost ~]# [root@localhost ~]#cat /proc/cpuinfo | egrep -o pse | head -n 1 pse [root@localhost ~]# ``` *Check if CPU supports HugePages 1GB Size* 命令如下，关键字是pdpe1gb ``` [root@localhost ~]# grep pdpe1gb /proc/cpuinfo | head -n 1 flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm fsgsbase smep arat [root@localhost ~]# [root@localhost ~]# egrep -o pdpe1gb /proc/cpuinfo | head -n 1 pdpe1gb [root@localhost ~]# ``` *How to change default HugePage size?* 默认大小为2MB ``` [root@localhost ~]# grep Hugepagesize: /proc/meminfo Hugepagesize: 2048 kB [root@localhost ~]# ``` 修改命令为 ``` [root@localhost ~]# grep GRUB_CMDLINE_LINUX /etc/sysconfig/grub GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet" [root@localhost ~]# [root@localhost ~]# vim /etc/sysconfig/grub [root@localhost ~]# grep GRUB_CMDLINE_LINUX /etc/sysconfig/grub GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet default_hugepagesz=1G" [root@localhost ~]# [root@localhost ~]# grub2-mkconfig -o /boot/grub2/grub.cfg Generating grub configuration file ... Found linux image: /boot/vmlinuz-5.2.14-1.el7.elrepo.x86_64 Found initrd image: /boot/initramfs-5.2.14-1.el7.elrepo.x86_64.img Found linux image: /boot/vmlinuz-3.10.0-957.27.2.el7.x86_64 Found initrd image: /boot/initramfs-3.10.0-957.27.2.el7.x86_64.img Found linux image: /boot/vmlinuz-3.10.0-693.el7.x86_64 Found initrd image: /boot/initramfs-3.10.0-693.el7.x86_64.img Found linux image: /boot/vmlinuz-0-rescue-f0b4bffdc9e44816abd201320f8a4f75 Found initrd image: /boot/initramfs-0-rescue-f0b4bffdc9e44816abd201320f8a4f75.img done [root@localhost ~]# [root@localhost ~]# reboot Connection closed by foreign host. [root@localhost ~]# grep Hugepagesize /proc/meminfo Hugepagesize: 1048576 kB [root@localhost ~]# ``` **参考资料** [Check if CPU supports HugePages & change default hugepage size in RHEL 7](https://www.golinuxcloud.com/change-default-hugepage-size-cpu-support-rhel/)