Topic: ATTN Litecoin GPU Miners - Scrypt support for cgminer - page 12. (Read 175855 times)

thanks for the hints ... I will try them ... after having some sleep and a day at work :-)

Not sure. I'm on 12.6 which gives me a decent buffer size but then I'm also running 7970s and it does appear to be affecting 5/6x and not 7x on linux. Also sdk2.6+ is mandatory with this. You could try making it ignore the reported limits and forcing higher values manually as well by --thread-concurrency and giving it higher multiples of 1440. Try with -g 1 to begin with so that you take that out of the equation at least. There are still far too many variables to know what's best with this FPOS.

system RAM is 2GB ... no other hungry processes running

I know that Linux drivers from AMD are not very good - with more than 1 card it can be a lottery to get the X server up without freezing the system ...

is there any chance another driver version has a higher memory buffer limit ?

Unfortunately this is nowhere near as logical as btc mining. Yes for some reason on linux the amd drivers aren't allowing larger buffer sizes. How much system ram do you have? You'll see it's setting concurrency to 1440 whereas something like 7200 is best, but that will ONLY work if the driver allows you to allocate ram. As for the reported hashrate, you are right in that once you go over the optimal values, it either starts doing work that returns less shares or starts creating invalid shares.

After a very good experience mining BTC with cgminer on p2pool for a few months I decided to try the scrypt version on one of my machines.

my experience with a 5850 is worse than what others report:

$ cgminer -o http://my_local_p2pool:9327 -u x -p y --scrypt --shaders 1440 -I 10

is doing only about 83 Kh/s

GPU 0: 83.5 / 83.6 Mh/s | A:129  R:3  HW:0  U:27.80/m  I:10
69.5 C  F: 34% (1819 RPM)  E: 900 MHz  M: 1000 Mhz  V: 1.118V  A: 99% P: 0%
Last initialised: [2012-07-25 02:24:44]
Intensity: 10
Thread 0: 41.6 Mh/s Enabled ALIVE
Thread 1: 41.9 Mh/s Enabled ALIVE


any higher intensity does not really work. p2pool logs many messages like this:

2012-07-25 02:32:18.484973 Worker x submitted share with hash > target:
2012-07-25 02:32:18.485073     Hash:   5a417c48970ce4d87e9b4c082f855a656a90a0e8e0e50a3c62c0dc6273e03b97
2012-07-25 02:32:18.485106     Target: 6b8bd775c948180000000000000000000000000000000000000000000000


at intensity 13 the hash rate estimate of p2pool stays way below 100, but cgminer reports about 250Kh/s and no rejected shares !

GPU 0: 242.5 / 93.2 Mh/s | A:270  R:3  HW:0  U:34.04/m  I:13
70.5 C  F: 60% (3633 RPM)  E: 900 MHz  M: 1000 Mhz  V: 1.118V  A: 99% P: 0%
Last initialised: [2012-07-25 02:24:44]
Intensity: 13
Thread 0: 123.9 Mh/s Enabled ALIVE
Thread 1: 126.5 Mh/s Enabled ALIVE


my configuration:
Linux 3.1.10-1.9 x86_64 GNU/Linux
AMD SDK V2.7
fglrx driver 12.6
cgminer commit bff58c3bed937bd027e46907acd1eab7327e838b compiled from git


cgminer -D -T reports

 [2012-07-25 02:11:38] Preferred vector width reported 4
 [2012-07-25 02:11:38] Max work group size reported 256
 [2012-07-25 02:11:38] Max mem alloc size is 134217728
 [2012-07-25 02:11:38] Selecting scrypt kernel
 [2012-07-25 02:11:38] GPU 0: selecting lookup gap of 2
 [2012-07-25 02:11:38] GPU 0: selecting thread concurrency of 1440
 [2012-07-25 02:11:38] Loaded binary image scrypt120724Cypressglg2tc1440w256l8.bin
 [2012-07-25 02:11:38] Initialising kernel scrypt120724.cl with bitalign, 1 vectors and worksize 256   
 [2012-07-25 02:11:38] Creating scrypt buffer sized 134217728
 [2012-07-25 02:11:38] initCl() finished. Found Cypress


any ideas what is wrong here ?

Guys come on... how exactly do you expect me to move forward without your help? I already said start it with "-D -T" added to your command line.

I don't know what debugging is. I'll just stick to

ckolivas-cgminer-3a0d60c
&
cgminer --scrypt -o http:// -u  -p  --worksize 256 --lookup-gap 2 --thread-concurrency 7200 -g 1 --intensity 19

Seems to work the best.

What debugging do you get running it with -D -T and then stopping it before it starts mining about size when you start it with --shaders 1440? Look for messages about buffer, lookup gap and thread concurrency.

cgminer's buffer build, thread concurrency, gap lookup and intensity/aggression work identically to raper so you will get identical buffer results, base performance etc with the same settings. The only thing I do differently is I check for errors when submitting the requests to opencl. You CAN override the upper limit for thread concurrency by just putting it in manually. However what likely happens is the error from the kernel running happens randomly. cgminer does not ignore the errors, whereas raper doesn't even check for them, it just keeps sending the kernel over and over ignoring whether it's working or not. Why linux has lower reported memory limits on this occasion to windows I don't know but I'm guessing it's just the driver differences. I could go in and make it ignore the results of failed kernel queueing, but that's so counter to good programming it's ridiculous. However it seems I have no choice...

Some of you Bitcoin purists really are scared of LTC aren't you?  Start your own thread if you'd like to discuss this.  I'm sure some would be more than happy to talk.  Otherwise STFU.

This thread is not the forum for that discussion.

It is impossible to design a proof-of-work that cannot be specialized (eg, ASICs). Designing them to be resistent to existing technologies increases the security risk such specialization presents. Simple proofs like SHA256 (in Bitcoin) have proven to work well, since it scales up in tiers (CPU -> GPU -> FPGA -> ASIC).

Could you go into more details on this one ?

Well considering you wrote that.  It's totally believable! lol.

Litecoin is a scam - there is no such thing as a "CPU coin" and never can be. I think Con is only doing this because he's being paid - in Bitcoins

https://en.bitcoin.it/wiki/Litecoin#Criticism

Okay, maybe I am being painfully slow today but...

1) Litecoin is intended to be a CPU coin, right ?

2) So, from this thread it appears that GPU mining it in a manner that is more economically effective than CPU mining is possible, right ?

But, if both 1 and 2 is true, doesn't that mean that litecoin is kinda...pointless?

This is horrible for me. 2 5850's.


cgminer --scrypt -o http://site:port -u username -p password --shaders 1440 --intensity 13

vs

809 khash/s


cgminer --scrypt -o http://site:port -u username -p password --worksize 256 --lookup-gap 2 --thread-concurrency 7200 -g 1 --intensity 19

Tesla M2050    79.8          1550    448    DiabloMiner
Tesla M2050    94.5          1550       poclbm

https://en.bitcoin.it/wiki/Mining_hardware_comparison#Nvidia

¤¿¤

Does CGminer-Scrypt support 1400 x Tesla M2050, the card BX use to launch the attack against litecoin network ?
How many kH/s you can get with that NVIDIA card ?
Is it bigger than 90 kH/s ?