Bmi2 and AMD

Leo · Post by **Leo** » Thu May 21, 2020 5:51 pm

Do we know if AMD has has fixed its Bmi2 problems?

MonteCarlo · Post by **MonteCarlo** » Thu May 21, 2020 6:27 pm

There was a recent update of an old thread http://talkchess.com/forum3/viewtopic.php?f=7&t=67432 that suggested there is no improvement.

I'm also not aware of any improvements, but I only follow these things loosely, so take with a grain of salt

Dann Corbit · Post by **Dann Corbit** » Thu May 21, 2020 7:03 pm

Compile for modern. A BMI compile on AMD is bad. Look at the BMI compiles here:
http://ipmanchess.yolasite.com/amd---in ... -bench.php

yurikvelo · Post by **yurikvelo** » Thu May 21, 2020 7:18 pm

Zen3 promise 10-15% IPC improvement.
Maybe they will implement hardware BMI2 execution as a part of this 10-15% target

AVX-512 is set to be only in Zen4 (along with DDR5)

yurikvelo · Post by **yurikvelo** » Fri May 22, 2020 12:40 am

Fishtest run BMI2 compiles for all AMD CPU with BMI2 support.
make ARCH=x86-64-bmi2

It's not good.

Leo · Post by **Leo** » Fri May 22, 2020 4:39 am

MonteCarlo wrote: ↑Thu May 21, 2020 6:27 pm There was a recent update of an old thread http://talkchess.com/forum3/viewtopic.php?f=7&t=67432 that suggested there is no improvement.

I'm also not aware of any improvements, but I only follow these things loosely, so take with a grain of salt

Thanks.

Bmi2 and AMD

Bmi2 and AMD

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Re: Bmi2 and AMD

Re: Bmi2 and AMD

Re: Bmi2 and AMD

Re: Bmi2 and AMD