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Meltdown-Spectre mitigation perfomance impacts?

Offline bunkobugsy

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« Last Edit: January 19, 2018, 02:09:28 AM by bunkobugsy »

Offline TerryF

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Re: Meltdown-Spectre mitigation perfomance impacts?
« Reply #16 on: January 19, 2018, 03:01:45 AM »
Strange as 9.2 iso has microcode_ctl-1.17-25.el6.x86_64.rpm   
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Offline TerryF

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Re: Meltdown-Spectre mitigation perfomance impacts?
« Reply #17 on: January 19, 2018, 03:04:22 AM »
--
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Offline bunkobugsy

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Re: Meltdown-Spectre mitigation perfomance impacts?
« Reply #18 on: January 19, 2018, 02:27:39 PM »
https://github.com/speed47/spectre-meltdown-checker

seems that kernel 2.6.32-696.18.7 is NOT VULNERABLE,

but I see no CPU microcode support (rather old Lenovo Bios)
« Last Edit: January 19, 2018, 02:38:09 PM by bunkobugsy »

Offline brianr

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Re: Meltdown-Spectre mitigation perfomance impacts?
« Reply #19 on: January 21, 2018, 12:05:54 PM »
Here's some interesting and relevant stuff

https://www.phoronix.com/scan.php?page=article&item=linux-415-fs&num=2

(benchmarking different file systems versus meltdown and spectre fixes  etc).

btrfs anyone?
« Last Edit: January 21, 2018, 12:09:09 PM by brianr »
Brian j Read
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The instrument I am playing is my favourite Melodeon.
.........

Offline DanB35

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Re: Meltdown-Spectre mitigation perfomance impacts?
« Reply #20 on: January 21, 2018, 01:43:51 PM »
btrfs anyone?
Good heavens, no.  Not if you care about your data, anyway.
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Offline brianr

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Re: Meltdown-Spectre mitigation perfomance impacts?
« Reply #21 on: January 21, 2018, 02:55:05 PM »
Good heavens, no.  Not if you care about your data, anyway.

Have you got a link that supports that comment?
Brian j Read
(retired, for a second time, still got 2 installations though)
The instrument I am playing is my favourite Melodeon.
.........

Offline Jean-Philippe Pialasse

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Re: Meltdown-Spectre mitigation perfomance impacts?
« Reply #22 on: January 21, 2018, 03:01:48 PM »
Reading this, the most impacted should be xfs, to make it as slow as ext4 and it is worst writing.

Offline DanB35

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Re: Meltdown-Spectre mitigation perfomance impacts?
« Reply #23 on: January 21, 2018, 07:45:15 PM »
Have you got a link that supports that comment?
The status page on the btrfs wiki is damning enough.  Parity RAID isn't stable and is broken by design (parity isn't checksummed, and it was coded with a write hole).  Mirrors are OK unless a disk fails (so, completely defeating the purpose of a mirror) ("needs at least two available devices always. Can get stuck in irreversible read-only mode if only one device is present.")

It's bad enough that even RedHat has finally dropped it: http://www.linux-magazine.com/Online/News/Red-Hat-to-Drop-Support-for-Btrfs
« Last Edit: January 21, 2018, 07:47:57 PM by DanB35 »
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Offline brianr

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Re: Meltdown-Spectre mitigation perfomance impacts?
« Reply #24 on: January 21, 2018, 08:31:38 PM »
The status page on the btrfs wiki is damning enough.  Parity RAID isn't stable and is broken by design (parity isn't checksummed, and it was coded with a write hole).  Mirrors are OK unless a disk fails (so, completely defeating the purpose of a mirror) ("needs at least two available devices always. Can get stuck in irreversible read-only mode if only one device is present.")

It's bad enough that even RedHat has finally dropped it: http://www.linux-magazine.com/Online/News/Red-Hat-to-Drop-Support-for-Btrfs

thanks Dan - that is damning.  shame...
Brian j Read
(retired, for a second time, still got 2 installations though)
The instrument I am playing is my favourite Melodeon.
.........

Offline DanB35

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Re: Meltdown-Spectre mitigation perfomance impacts?
« Reply #25 on: January 21, 2018, 08:41:13 PM »
It's unfortunate that RedHat won't use ZFS--there's an existing, stable, next-generation filesystem that does most of what btrfs was supposed to, and does it well.  What it doesn't do (yet) is allow RAID expansion or reduction, which btrfs is supposed to--and would be great, if the rest of the filesystem were stable.
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