GPU plot generator v4.1.1 (Win/Linux)
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Hi guys,
Bit of weirdness with this, maybe the latest update fixed it?
Have an Nvidia Titan X, and using 0 1 4096 128 10 as the device settings.
The plot being set as _3814592_64
The first 99% will complete as fast as the drive can write, (Samsung EVO 960 NVMe M.2 1TB) but the last 1% drops down to, Kb/sec. Considering this drive can read/write at 2000/2000Mb/s just wondered what this massive drop in performance is down to at the end?
Thankyou.
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So downloaded the latest version, and no different, it writes a massive amount of data very quickly, then, bam, slows down writing the nonces at 4332/minute direct mode on a 2000/2000Mb drive.
The CPU can write at 4x that, so I have no idea why the performance on this floors out so hard?
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@XenForoSlavik having the same problem, performance drops and it's not constant @cryo
0meh 14 yr old kid trying to fit in.
My asset :) https://forums.burst-team.us/topic/5539/hidevin-ann
Asset ID:8094717548345959327
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@HiDevin Quite, I have 2 titans now plotting at 70-80k nonces per minute in buffer mode, and the drive is laughing at the "pathetic" 300-400Mb/s write rate, yes, the drive is able to write faster than 2 graphics cards can give it data... so maybe im misunderstanding how the direct mode works, but something is quite drastically wrong when a CPU plotter can do it quicker.
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@XenForoSlavik You're writing 3,815,592 values, in chunks of 64 values at a time, so around 59,000 blocks of scoops. When you start mining that,the miner will go seek to the first set of nonces, and read those 64, then seek to the 2nd set of nonces and read them, then seek to the 3rd set of nonces and read them ....... Disk seeks are computationally incredibly bad. Your cpu that can do billions of computations per second, is stuck waiting while the disk drive head moves, and more data can be read. Seek times are measured in milliseconds, to us that incredibly fast, to a CPU it's an eternity, and with your method of plotting, there are almost 60,000 seeks to mine a single plot.
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@haitch At the moment I am simply trying to work out how to get the GPU writer to write out at a decent rate in direct mode. However, I can not work out why it will write out 99% of the plot at full speed, then on the last 1% it slows down to an absolute crawl.
I updated to the latest build, and even with the pre-alocated space, it seems incapable of writing faster than 5k nonces a minute in direct mode. At first I suspected the hard drives, but after grabbing this M.2 drive to rule that out today, I can only guess theres an issue with the write out logic of the gpu writer, unless you have suggestions on other configs?
Device settings: 0 1 4096 512 1024
Drive size: 1,000,068,808,704 bytes
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@XenForoSlavik If you're basically stopping plotting towards the end of your plot, you've set the number of nonces to high.
The miner will write multiples of your stagger, up to the value of your number of nonces. But if number of nonces is not a multiple of the stagger, the plotter will round up and try to plot 101% of your hard disk.
To calculate the correct number of nonces to use in your plot: floor((disk size in bytes / 262144) div <stagger>) * stagger
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@haitch To test this, I created a 200Gb plot on the drive: 819200_8192
This was the result:
Now, did the same with Xplotter:
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@XenForoSlavik I see a plotter plotting - am I missing something ?
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@haitch said in GPU plot generator v4.1.1 (Win/Linux):
@XenForoSlavik I see a plotter plotting - am I missing something ?
Yes, the appalling speed. The first one is the GPU plotter... the second is Xplotter.
Unless a GPU (Titan X) writing in direct mode at 1/3 the speed of a cpu is expected? When in buffer mode it can write at 35-40k.
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@XenForoSlavik When writing in direct mode, gpuplotgenerator prior to the latest version goes through two stages - first it builds the file to hold the plot - depending on the drive size, this can be a day or more. Once built it then starts filling it in with plotted nonces. During Phase 1 your plotting rate will drop to miserable values, then during phase 2 it'll keep increasing.
However, @cryo has released a new version of gpuplotgenaerator, that when run as admin totally skips the slow build the file phase. Kill you plot and grab the new version and restart.
