Performance anyone?!

[p2501]

Okay I was searching for some additional stats for poclbm. What I found was the following:

http://forum.bitcoin.org/index.php?topic=22965.0

I'm quoting here:

You can go to phatk's kernel.cl file (don't worry, it just sits there in the open, no need to recompile anything), find this line
  #define Ma(x, y, z) amd_bytealign((y), (x | z), (z & x))
and change it to this line
  #define Ma(x, y, z) amd_bytealign( (z^x), (y), (x) )
Once you've done it, restart the miner.

Using phoenix you find both kernels in the kernels folder (I know, kind of obvious, isn't it?! ). This modification works for both kernels but only if you're using BFI_INT.

My results: Cayman cores gain ~14MHash consistently. 5xxx cores should gain even more.

[Alpha]

hmm... i am going to have to try this... i could use an extra few hashes...

reporting back in a few...

update:

ok, went from ~308 mh/s on my 5830's at 1000/300 to ~ 315mh/s with just this change

[dairyFarmer]

Thanks, I just tried this out and got an extra 9 Mh/s on each of my 5830's.
Im running phatk in guiminer June 2011 release.

[Jen]

worked for me as well , better stable mhash

Jen

[OldChap]

+10 and 12 for me on 5870's Thanks p

[KaptainBlaZzed]

worked for me.

Nice find.

[jcool]

If anything, this had a negative effect for me. Running 5870's on 2.1 SDK with poclbm, I went from 395-398 to 389-395 @ 900 core.

[OldChap]

I only have 5870's which on sdk 2.4, phoenix, phatk and this mod will run 400Mhash/sec @ core 900 now all I need is a working auto re-start for miners "connecting" longer than x seconds

[Musho]

I only have 5870's which on sdk 2.4, phoenix, phatk and this mod will run 400Mhash/sec @ core 900 now all I need is a working auto re-start for miners "connecting" longer than x seconds

Had problems with auto reconnecting with Phoenix 1.48 as well. 1.50 fixed this completely for me! Up and running for close to 2 days now, with a few disconnects in between. Didn't have to manually interfere a single time! Might be worth downloading the new release Don't forget applying this mod to the freshly downloaded 1.50 build

[cajer]

Mhashes went up from 315 to 330 on my 6950's, but stales are uncomfortably high at 2.2%.

[Musho]

Mhashes went up from 315 to 330 on my 6950's, but stales are uncomfortably high at 2.2%.

That's almost a 5% increase in MHashes/Sec, so it's actually performing better, even though you are getting a higher percentage stales. So don't worry too much about it

[Tom128]

I updated my 5 cards all of which had a good gain from this

Now I just need to figure out why I have ONE card that keeps losing its connection and sits there for the entire day when I am at work connecting. It's a 5830, in a machine with a second 5830, using the exact same settings. The other one has NEVER went idle, this one does it daily. I went home for lunch today and restarted it, and just saw on BTCGuilds page that the same one has yet again stopped.

[don_xvi]

Maybe just try putting that one card onto another pool?

[OldChap]

If running wcg too try moving to just cancer or something like that or freeing up a core so your miner always has cpu available... and try phoenix 1.50 as mentioned above.

If you have an alternate gigabit card or port maybe look at that too.

[Tom128]

I was still running 1.48, switched to 1.5 hopefully that helps. I had 3 cards stalled when I got home today Not sure what they changed in the new phoenix but the file size went from 22k to over 6MB Looks like they also changed the output pattern, GPUMiner does not report the speed anymore, but it does report the accepted/stales at least. I ran it on the command line just to see and I got a slight Mhash increase as well, like 3 per card.