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