[Cin] Help with performance problems

Andrea paz gamberucci.andrea at gmail.com
Sun Dec 8 13:20:58 CET 2019

Some of the advice I've accumulated over the years:
1- Eliminate Spectre mitigations and other CPU security flaws. These
in fact remove multithreading. If one makes a home use it is
permissible to remove security patches, but it is a decision that
everyone must evaluate for themselves. It seems to me that AVLinux
uses Grub as its boot loader. In this case you have to put the entry
"mitigations=off" inside the grub configuration file, under the entry
"GRUB_CMDLINE_LINUX_DEFAULT". Ask Glenn for precise instructions.
2- Intervene in CFLAGS and CXXFLAGS by putting "march=native" and
"-mtune=native" in place of the generic "-march=x86_64" and
"-mtune=generic". Decomment "MAKEFLAGS=-j2" and bring the value to 16.
In Arch linux it's easy, but in AVLinux I don't know how to do it. You
have to ask Glenn on his forum. Also I'm not sure they serve for a
Xeon, but I think so.
3- Install the "Irqbalance" program and then start and enable its
service in systemd (AVLinux uses systemd?):
# systemctl start/enable irqbalance.service
This program serves to better balance the distribution of calculations
in the various threads. Actually, I'm not sure that it's still useful
these days.

Finally, I do not recommend using vaapi or vdpau for encoding; it
produces results quickly but of poor quality. Better to use them for
decoding only.

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