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From Dor Laor <...@scylladb.com>
Subject Re: Meltdown/Spectre Linux patch - Performance impact on Cassandra?
Date Tue, 09 Jan 2018 18:30:23 GMT
Make sure you pick instances with PCID cpu capability, their TLB overhead
flush
overhead is much smaller

On Tue, Jan 9, 2018 at 2:04 AM, Steinmaurer, Thomas <
thomas.steinmaurer@dynatrace.com> wrote:

> Quick follow up.
>
>
>
> Others in AWS reporting/seeing something similar, e.g.:
> https://twitter.com/BenBromhead/status/950245250504601600
>
>
>
> So, while we have seen an relative CPU increase of ~ 50% since Jan 4,
> 2018, we now also have applied a kernel update at OS/VM level on a single
> node (loadtest and not production though), thus more or less double patched
> now. Additional CPU impact by OS/VM level kernel patching is more or less negligible,
> so looks highly Hypervisor related.
>
>
>
> Regards,
>
> Thomas
>
>
>
> *From:* Steinmaurer, Thomas [mailto:thomas.steinmaurer@dynatrace.com]
> *Sent:* Freitag, 05. Jänner 2018 12:09
> *To:* user@cassandra.apache.org
> *Subject:* Meltdown/Spectre Linux patch - Performance impact on Cassandra?
>
>
>
> Hello,
>
>
>
> has anybody already some experience/results if a patched Linux kernel
> regarding Meltdown/Spectre is affecting performance of Cassandra negatively?
>
>
>
> In production, all nodes running in AWS with m4.xlarge, we see up to a 50%
> relative (e.g. AVG CPU from 40% => 60%) CPU increase since Jan 4, 2018,
> most likely correlating with Amazon finished patching the underlying
> Hypervisor infrastructure …
>
>
>
> Anybody else seeing a similar CPU increase?
>
>
>
> Thanks,
>
> Thomas
>
>
>
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