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Bitcoin => Bitcoin Technical Support => Topic started by: jefferson7 on July 25, 2017, 01:26:14 PM



Title: BTc Core re-indexing taking days! (Linux)
Post by: jefferson7 on July 25, 2017, 01:26:14 PM
Im trying to re-index the blockchain to avoid having to download it again (slow connection).

Its taking days. Im using Linux and the processor use is under 10%!
Does anyone know how to increase that? I've adjusted the DBcache size up very high and tried out using the Error check threads that are available in options and when I launch Bt caore it runs at 50% for a while and gradually slows down to under 10%.

Does anyone have any tips to speed this up? Surely it should be at 50% more or less all the time? !00% would be great.
The disk use isnt very high either.


Title: Re: BTc Core re-indexing taking days! (Linux)
Post by: Turner77 on July 26, 2017, 04:44:31 PM
Im trying to re-index the blockchain to avoid having to download it again (slow connection).

Its taking days. Im using Linux and the processor use is under 10%!
Does anyone know how to increase that? I've adjusted the DBcache size up very high and tried out using the Error check threads that are available in options and when I launch Bt caore it runs at 50% for a while and gradually slows down to under 10%.

Does anyone have any tips to speed this up? Surely it should be at 50% more or less all the time? !00% would be great.
The disk use isnt very high either.

FWIW -   I've done informal monitoring on my PC as it's been syncing Bitcoin Core for the first time.

Based on what I've seen the overall performance is limited  by the code only using a single core to run the hash, which means the CPU cycle time is a bottleneck. 

So a faster single core CPU beats a slower multi-core on a lot of the work I am seeing.

Not sure if that's an issue with the re-indexing, because that might be due to the database code.


Title: Re: BTc Core re-indexing taking days! (Linux)
Post by: ZenFr on July 26, 2017, 09:03:49 PM
Im trying to re-index the blockchain to avoid having to download it again (slow connection).

Its taking days. Im using Linux and the processor use is under 10%!
Does anyone know how to increase that? I've adjusted the DBcache size up very high and tried out using the Error check threads that are available in options and when I launch Bt caore it runs at 50% for a while and gradually slows down to under 10%.

Does anyone have any tips to speed this up? Surely it should be at 50% more or less all the time? !00% would be great.
The disk use isnt very high either.
Stop the virtual threads in your BIOS and if it is not enough, stop the multithreading : you will work on only one core but with the maxium turbo frequency (if you use Intel CPUs, AMD CPUs are very slows in all cases).


Title: Re: BTc Core re-indexing taking days! (Linux)
Post by: Mad7Scientist on July 27, 2017, 04:42:33 PM
What's the CPU use of bitcoin in top? Unlike Windows, it will show 110% for 100% of 1 core use and 10% use of your CPU's second core. Are you sure you're not downloading the blockchain? It may do so if the blocks are somehow corrupted. Did you start bitcoin-qt with -reindex?

A pentium 4 3.0GHz syncs through 2015 at about 30 times the normal rate, or 20 seconds per block instead of 10 minutes.

When you get in to the more recent blocks more and more (like 6GB) RAM will be needed to reduce disk I/O.