Re: [IT-SecNots] High CPU usage after upgrading from Debian 7 to Debian 9

[Matus UHLAR - fantomas <uhlar AT fantomas.sk>]

On 15.04.19 11:05, Алексей wrote:
> I have two Debian boxes acting as a routesr (+iptables +quagga(BGP)). I have 
> updated one from Debian 7 to Debian 9 recently and now experience 2x CPU 
> utilization on the same amounts of traffic, e.g. on normal load of 1Gbps 
> (real-world traffic) Debian 7 had 5-6% and Debian 9 has 10-12% softirq CPU 
> time. This behaviour can also be observed during tests - 6Gbps iperf gets 3% 
> on Debian 7 and 6% on Debian 9.
>
> I compared ethtool -k outputs on both boxes and they are pretty similar. 
> Syslog doesn't show anything suspicious.
>
> Did anyone have the similar issue? Or can give me some advice on 
> troubleshooting?

we have noticed something similar due to the spectre/meltdown updates.
Turning off HT cpus did help much.
not installing the CPU microcode should help too.

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Matus UHLAR - fantomas, uhlar AT fantomas.sk ; http://www.fantomas.sk/
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