Topic: CCminer(SP-MOD) Modded NVIDIA Maxwell / Pascal kernels. - page 778. (Read 2347664 times)

Quote from: sp_ on January 28, 2016, 01:32:06 AM

this is in the cpu verification code. The gpu code is different. There we have precalc tables of the states to avoid conditional branches.

Whatever it is it's faster.

The cpu verification is only done when the gpu find a solution.

I know why changing the verification code made things faster. I wa scpumining 8
threads at the time so it was slowing down the CPU.

But in ccminer you can just remove the verification. It's there so that you can check if you break the hash when you change something.

Tried that in cpuminer, didn't help. I only managed to get another 1% out of c11, not sure why, expected more,
will take another look.

No other algos benefit from the fast ctx reinit but you should try it in ccminer, the GPU kernel, that is.

joblo

legendary

Activity: 1470

Merit: 1114

Quote from: joblo on January 27, 2016, 10:42:51 PM

You are an ssembly language guy, do you reorder instructions to maximize instruction throughput.
It requires detail knowledge of theprocessor such as how many instructions can be fetched per clock,
how many can be executed per clock, how deep is the memory buffer, dies it delay writes to prioritize
reads?, how big is a cache line, etc. I know none of this stuff, maybe you do and could use it to speed
up the hot spots.

This is something the compiler is very good at. The cudacore is a 3 + operation risc processor with up to 256 registers.
It is buildt for the compiler..

Sometimes you need to move code around, manually unroll some loops etc.. Verify the result with disassembling. (this is what DJM34 is calling random stuff)

But don't let the codesize grow to big, the instruction cache is small.
...

While you where trolling my thread I added another 0.4% in the decred algo.
I will try to do 5% and include it in my donation miner.

I wastalking more about performing loads as soon as possible to give time for mem to respond before
you need the data. It also fills the cache line for susequent loads. If cuda supports read priority you
can even issue a store before a load and the load will have priority. You just have to watch for register
conflicts.

There is also issuing different types of instructions on the same clock to improve superscalar
operation.

These kinds of things are hard for a normal compiler to do because it is specific to each processor,
but if anyone can do it it'd cuda because thy have one HW architecture, one run time system and
one compiler.

And another thing, you trolled me first.

sp_

legendary

Activity: 2954

Merit: 1087

Team Black developer

Quote from: joblo on January 27, 2016, 08:12:09 PM

Quote from: joblo on January 27, 2016, 10:42:51 PM

this is in the cpu verification code. The gpu code is different. There we have precalc tables of the states to avoid conditional branches.

Whatever it is it's faster.

The cpu verification is only done when the gpu find a solution.

I know why changing the verification code made things faster. I wa scpumining 8
threads at the time so it was slowing down the CPU.

But in ccminer you can just remove the verification. It's there so that you can check if you break the hash when you change something.

sp_

legendary

Activity: 2954

Merit: 1087

Team Black developer

You are an ssembly language guy, do you reorder instructions to maximize instruction throughput.
It requires detail knowledge of theprocessor such as how many instructions can be fetched per clock,
how many can be executed per clock, how deep is the memory buffer, dies it delay writes to prioritize
reads?, how big is a cache line, etc. I know none of this stuff, maybe you do and could use it to speed
up the hot spots.

This is something the compiler is very good at. The cudacore is a 3 + operation risc processor with up to 256 registers.
It is buildt for the compiler..

Sometimes you need to move code around, manually unroll some loops etc.. Verify the result with disassembling. (this is what DJM34 is calling random stuff)

But don't let the codesize grow to big, the instruction cache is small.
...

While you where trolling my thread I added another 0.4% in the decred algo.
I will try to do 5% and include it in my donation miner.

joblo

legendary

Activity: 1470

Merit: 1114

You are an ssembly language guy, do you reorder instructions to maximize instruction throughput.
It requires detail knowledge of theprocessor such as how many instructions can be fetched per clock,
how many can be executed per clock, how deep is the memory buffer, dies it delay writes to prioritize
reads?, how big is a cache line, etc. I know none of this stuff, maybe you do and could use it to speed
up the hot spots.

joblo

legendary

Activity: 1470

Merit: 1114

this is in the cpu verification code. The gpu code is different. There we have precalc tables of the states to avoid conditional branches.

Whatever it is it's faster.

The cpu verification is only done when the gpu find a solution.

I know why changing the verification code made things faster. I wa scpumining 8
threads at the time so it was slowing down the CPU.

joblo

legendary

Activity: 1470

Merit: 1114

this is in the cpu verification code. The gpu code is different. There we have precalc tables of the states to avoid conditional branches.

Whatever it is it's faster.

The cpu verification is only done when the gpu find a solution.

I may not have realized I was looking at verification code at the time but I know what it is.
Maybe my changes can be applied to the GPU code and you'll get your 30%

joblo

legendary

Activity: 1470

Merit: 1114

this is in the cpu verification code. The gpu code is different. There we have precalc tables of the states to avoid conditional branches.

My changes have nothing to do with avoiding branches but avoiding work.

sp_

legendary

Activity: 2954

Merit: 1087

Team Black developer

this is in the cpu verification code. The gpu code is different. There we have precalc tables of the states to avoid conditional branches.

Whatever it is it's faster.

The cpu verification is only done when the gpu find a solution.

joblo

legendary

Activity: 1470

Merit: 1114