Author

Topic: Throughput calculations? (Read 1517 times)

sr. member
Activity: 262
Merit: 250
March 19, 2013, 07:33:14 PM
#11
You're not looking for a nonce. You're using the nonce to look for a share. Sometimes you can find 2 shares per nonce range. Sometimes it's zero.

Ah. That explains it. Thanks!
legendary
Activity: 1750
Merit: 1007
March 19, 2013, 05:31:35 PM
#10
Think of it like rolling dice.  Your odds of getting a 6 is 1 in 6.  If you're only going to make 3 rolls, you have an ~50% chance to get a 6 in one of those rolls.  However, if you were going to make 3,000 rolls, you're much more likely to be in the expected 16.67% of rolls actually being 6.

But miner's aren't rolling a dice. They don't use a random function to guess the nonce (or do they?).

They usually start counting from 0 up to 2^32 -1 in order not to check the same value multiple times. On the average they will find the nonce half way through the sequence.
You're not looking for a nonce. You're using the nonce to look for a share. Sometimes you can find 2 shares per nonce range. Sometimes it's zero.

Exactly as crazyates said.  You're not guaranteed to find a share in a nonce range, so it's not like you can start at 0, count up, and when you find one, you know you found "the" nonce in the range and can start over.  So it is like dice.  Just because you rolled a 1 doesn't mean you won't roll it again before you get your 6.
legendary
Activity: 952
Merit: 1000
March 19, 2013, 05:23:25 PM
#9
Think of it like rolling dice.  Your odds of getting a 6 is 1 in 6.  If you're only going to make 3 rolls, you have an ~50% chance to get a 6 in one of those rolls.  However, if you were going to make 3,000 rolls, you're much more likely to be in the expected 16.67% of rolls actually being 6.

But miner's aren't rolling a dice. They don't use a random function to guess the nonce (or do they?).

They usually start counting from 0 up to 2^32 -1 in order not to check the same value multiple times. On the average they will find the nonce half way through the sequence.
You're not looking for a nonce. You're using the nonce to look for a share. Sometimes you can find 2 shares per nonce range. Sometimes it's zero.
sr. member
Activity: 262
Merit: 250
March 19, 2013, 02:00:58 PM
#8
Think of it like rolling dice.  Your odds of getting a 6 is 1 in 6.  If you're only going to make 3 rolls, you have an ~50% chance to get a 6 in one of those rolls.  However, if you were going to make 3,000 rolls, you're much more likely to be in the expected 16.67% of rolls actually being 6.

But miner's aren't rolling a dice. They don't use a random function to guess the nonce (or do they?).

They usually start counting from 0 up to 2^32 -1 in order not to check the same value multiple times. On the average they will find the nonce half way through the sequence.
legendary
Activity: 1750
Merit: 1007
March 19, 2013, 01:08:44 PM
#7
It is known that on average, it takes 4.2 billion hashes to create a difficulty 1 share.

That was the answer to my question.

But how do you come up with that number? There are 4294967296 different nonce values (32-bit). If you iterate over all possible values your will find a hit every 2147483648 on the average, or roughly 2Ghash operations. Is this the assumption?



Think of it like rolling dice.  Your odds of getting a 6 is 1 in 6.  If you're only going to make 3 rolls, you have an ~50% chance to get a 6 in one of those rolls.  However, if you were going to make 3,000 rolls, you're much more likely to be in the expected 16.67% of rolls actually being 6.
sr. member
Activity: 262
Merit: 250
March 19, 2013, 12:45:48 PM
#6
It is known that on average, it takes 4.2 billion hashes to create a difficulty 1 share.

That was the answer to my question.

But how do you come up with that number? There are 4294967296 different nonce values (32-bit). If you iterate over all possible values your will find a hit every 2147483648 on the average, or roughly 2Ghash operations. Is this the assumption?

vip
Activity: 980
Merit: 1001
March 19, 2013, 12:18:32 PM
#5
if you mean hashrate
most pools take an average of shares submitted over a time period to give miners an estimate of hashrate

Yes. I mean hashrate.

But how do they know how many hash calculations you did per second for a given submit? Do they assume that you got there by incrementing the nonce  by one until you submitted?

they do not know what your miner is actually doing
all a pool can do is estimate a hashrate based on shares returned to the pool
legendary
Activity: 1750
Merit: 1007
March 19, 2013, 12:17:04 PM
#4
BTC Guild's dashboard uses a growing averaging window.  After shares have been submitted for about 1 minute, it will begin to estimate your hash rate.  As more time is measured, it increases the amount of data used to guess more accurately, up to 1 full hour of share submissions.  If a 10 minute gap is seen in your history, it will reset that estimate to only most recent submissions until there is no longer a gap.


EDIT:  More detailed explanation.  Pools in general use your share submissions to GUESS your hash rate.  It is known that on average, it takes 4.2 billion hashes to create a difficulty 1 share.  By dividing the number of shares you've submitted over a time frame, it can guess your approximate hash rate.  The faster you hash, the more accurate this will be, because the pool has a more consistent set of data to work with.  This is why very slow miners (CPUs/nVidia) rarely have an accurate estimate on any pool.  If your share submissions are slow, it's difficult to get a good estimate due to the small sample size.
sr. member
Activity: 262
Merit: 250
March 19, 2013, 12:02:19 PM
#3
if you mean hashrate
most pools take an average of shares submitted over a time period to give miners an estimate of hashrate

Yes. I mean hashrate.

But how do they know how many hash calculations you did per second for a given submit? Do they assume that you got there by incrementing the nonce  by one until you submitted?
vip
Activity: 980
Merit: 1001
March 19, 2013, 11:36:13 AM
#2
if you mean hashrate
most pools take an average of shares submitted over a time period to give miners an estimate of hashrate

Ozcoin uses a rolling 5 minute period
sr. member
Activity: 262
Merit: 250
March 19, 2013, 11:01:48 AM
#1
How do the pools calculate your mining hash throughput?
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