For what it’s worth, we (TLP) just posted some results comparing pre and post meltdown statistics: http://thelastpickle.com/blog/2018/01/10/meltdown-impact-on-latency.html <http://thelastpickle.com/blog/2018/01/10/meltdown-impact-on-latency.html>
> On Jan 10, 2018, at 1:57 AM, Steinmaurer, Thomas > <thomas.steinmau...@dynatrace.com> wrote: > > m4.xlarge do have PCID to my knowledge, but possibly we need a rather new > kernel 4.14. But I fail to see how this could help anyway, cause this looks > highly Amazon Hypervisor patch related and we do not have the production > instances patched at OS/VM level (yet). <> > > Thomas > > From: Dor Laor [mailto:d...@scylladb.com] > Sent: Dienstag, 09. Jänner 2018 19:30 > To: user@cassandra.apache.org > Subject: Re: Meltdown/Spectre Linux patch - Performance impact on Cassandra? > > 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.steinmau...@dynatrace.com <mailto:thomas.steinmau...@dynatrace.com>> > wrote: > Quick follow up. <> > > Others in AWS reporting/seeing something similar, > e.g.:https://twitter.com/BenBromhead/status/950245250504601600 > <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.steinmau...@dynatrace.com > <mailto:thomas.steinmau...@dynatrace.com>] > Sent: Freitag, 05. Jänner 2018 12:09 > To: user@cassandra.apache.org <mailto: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 > > The contents of this e-mail are intended for the named addressee only. It > contains information that may be confidential. Unless you are the named > addressee or an authorized designee, you may not copy or use it, or disclose > it to anyone else. If you received it in error please notify us immediately > and then destroy it. Dynatrace Austria GmbH (registration number FN 91482h) > is a company registered in Linz whose registered office is at 4040 Linz, > Austria, Freistädterstraße 313 > <https://maps.google.com/?q=4040+Linz,+Austria,+Freist%C3%A4dterstra%C3%9Fe+313&entry=gmail&source=g> > The contents of this e-mail are intended for the named addressee only. It > contains information that may be confidential. Unless you are the named > addressee or an authorized designee, you may not copy or use it, or disclose > it to anyone else. If you received it in error please notify us immediately > and then destroy it. Dynatrace Austria GmbH (registration number FN 91482h) > is a company registered in Linz whose registered office is at 4040 Linz, > Austria, Freistädterstraße 313 > <https://maps.google.com/?q=4040+Linz,+Austria,+Freist%C3%A4dterstra%C3%9Fe+313&entry=gmail&source=g> > > The contents of this e-mail are intended for the named addressee only. It > contains information that may be confidential. Unless you are the named > addressee or an authorized designee, you may not copy or use it, or disclose > it to anyone else. If you received it in error please notify us immediately > and then destroy it. Dynatrace Austria GmbH (registration number FN 91482h) > is a company registered in Linz whose registered office is at 4040 Linz, > Austria, Freistädterstraße 313
