Michael wrote: > On Saturday, 2 May 2020 10:54:02 BST Dale wrote: >> Michael wrote: >>> I'd be interested to know as a comparison if Nikos' and Dale's I/O >>> unresponsiveness in swapping sees an improvement with the I/O scheduler >>> for >>> spinning drives set to bfq; e.g.: >>> >>> echo bfq > /sys/block/sda/queue/scheduler >> This is its setting at the moment. >> >> >> root@fireball / # cat /sys/block/sda/queue/scheduler >> noop deadline [cfq] >> root@fireball / # > Ahh, you must be on an older kernel? > > I'm on 5.4.28 here and these are the new kernel scheduler options: > > # > # IO Schedulers > # > CONFIG_MQ_IOSCHED_DEADLINE=y > CONFIG_MQ_IOSCHED_KYBER=y > CONFIG_IOSCHED_BFQ=y > CONFIG_BFQ_GROUP_IOSCHED=y > # CONFIG_BFQ_CGROUP_DEBUG is not set > # end of IO Schedulers > > The BFQ scheduler has a number of tunable parameters via sysctl, like weight, > latency and what not, but unless you're into running endless benchmark tests > to tune your particular devices, I'd leave it to do its thing with default > settings. >
Yea, I got new UPS batteries coming which means a complete power down. I may upgrade my kernel before doing that. It slipped my mind so glad this came up. I'm on 4.19.40-gentoo but I need to see what is the latest version nvidia-drivers supports first. I guess I'll google that or something. >> I know I can echo it in but where do I set that to that when booting? > You can set a local script to switch from other schedulers - the default is > mq-deadline - or you can disable the others in the kernel. I don't know if > you can pass an option to the kernel line at boot time. > > I understand this is more effective with slow(er) spinning drives and perhaps > old SSDs. NVMe drives won't benefit from it and are better run with the > default mq-deadline scheduler. I googled it, it seems it gets added to the kernel line options via grub2's conf file. I have another option there too, IOMMU or something like that. Right now, it's off to the tractor and discing up my garden. So much rain lately, I'm just now able to get a tractor in it. New disc is awesome tho. Oh, for future reference: # cat /etc/sysconfig/grub GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)" GRUB_DEFAULT=saved GRUB_DISABLE_SUBMENU=true GRUB_TERMINAL_OUTPUT="console" GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet elevator=cfq" GRUB_DISABLE_RECOVERY="true" It's the 2nd line from the bottom. It may be configurable in menuconfig too. I dunno know yet. I'll try to look. Must make note to upgrade kernel. Batteries will be here Monday. Thanks much. It's on my todo list. Dale :-) :-)
