On Tue, Nov 13, 2001 at 03:13:29PM +0000, David Malone wrote: > > I'm trying to test and tune speed of freebsd's filesystem in many aspects. > > I run recent FreeBSD 4.4-STABLE with new dirprefs code, read tuning(7), > > newfs'd my FS, turned softupdates on, have UFS_DIRHASH kernel option. > > Also, I've read DIRHASH kernel code source. It seems that efficiency of > > DIRHASH greatly depends of kernel memory size (and some experiments > > approve this). > > You should be able to control how much memory is used by dirhash > with the vfs.ufs.dirhash_maxmem sysctl. By default it uses up to > 2MB and it should be possible to raise it significantly, providing > you have enough physical memory. (By default there is about 1GB of > kernel address space, so you are unlikely to be running into this > limit - I don't think changing kern.vm.kmem.size will help you).
Are you shure? From LINT: # Tune the kernel malloc area parameters. VM_KMEM_SIZE represents the # minimum, in bytes, and is typically (12*1024*1024) (12MB). # VM_KMEM_SIZE_MAX represents the maximum, typically 200 megabytes. # VM_KMEM_SIZE_SCALE can be set to adjust the auto-tuning factor, which # typically defaults to 4 (kernel malloc area size is physical memory # divided by the scale factor). # options VM_KMEM_SIZE="(10*1024*1024)" options VM_KMEM_SIZE_MAX="(100*1024*1024)" options VM_KMEM_SIZE_SCALE="4" It seems DIRHASH is limited with free space in the kernel malloc area. It even cannot utilize default 2M of vfs.ufs.dirhash_maxmem when I do not increase kern.vm.kmem.size. I think it's because of kernel malloc area exhaustion. However, when I increase kern.vm.kmem.size upto 64M and vfs.ufs.dirhash_maxmem upto 8M, it starts using more than 2M of dirhash memory and speed of my tests greatly improves. So, how can I estimate needed value of kern.vm.kmem.size? Eugene Grosbein To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
