qemu-x86_64 fails on A72 cores, but runs nice on A53 ones :)
#7
Smile 
(11-03-2018, 08:43 PM)guannais Wrote: Thanks for the performance advice [Image: smile.png]

Since "qemu" recompiles the code on the fly it may be a problem with the code generator for ARM. What is strange is that any A72 core should be binary compatible with any A53 one, just the armv8-a instruction set.

I was compiling with those flags:

Code:
CFLAGS="-march=armv8-a+simd+crc -mtune=cortex-a53 -mfix-cortex-a53-843419 -Os -pipe"
which I inherited from the setup of my Odroid-C2.

You welcome,

In theory,
Code:
-march=armv8-a+crypto+crc

Should enable: { "[font=monospace]fp asimd" + "aes pmull sha1 sha2" } + { "crc32" }[/font]

But if you look into the definitions, that its not clear..
https://code.woboq.org/gcc/gcc/config/aa...s.def.html

So better do a explicit request:

Code:
-march=armv8-a+simd+crypto+crc
This should enable: [font=monospace]{ [/font][font=monospace]"[/font][font=monospace][font=monospace]fp asimd" } + { "[/font][/font][font=monospace]a[/font][font=monospace]es[/font][font=monospace] pmu[/font][font=monospace]ll[/font][font=monospace] [/font][font=monospace]sha1 sha2[/font][font=monospace]" [/font][font=monospace]}[/font][font=monospace] +[/font][font=monospace] { "[/font][font=monospace]crc32[/font][font=monospace]" }[/font]
not sure about: [font=monospace][font=monospace]" [/font][/font][font=monospace][font=monospace][font=monospace][font=Monaco, Consolas, Courier, monospace]evtstrm [/font]: kernel event stream using generic architected timer.. [/font][/font][/font][font=monospace][font=monospace]"[/font][/font]

I think that landed in gcc 8.x, when you use crypto, it already add fp+simd, but I don't know if its already in stable version.. so I tell him explicitly to use the extensions..


Messages In This Thread
RE: qemu-x86_64 fails on A72 cores, but runs nice on A53 ones :) - by tuxd3v - 11-04-2018, 01:20 PM

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