Eric Voskuil

Eric Voskuil Verified account @evoskuil · 10h

Right, sequential block validation results in CPU starvation. That's not as visible when running on low capacity hardware, which is why we have always tested at a minimum of 64 threads, and now 128. At lower power other things dominate. It's like testing for bandwidth limitation on a very slow network. Of course that will always look network limited.

bitcoind, which is very efficient at single block validation after 17 years of tuning, uses only 15% mean CPU in full validation on the machine in the OP, bs uses 88% mean. If we run that on Lopp's benchmark or a RPi they are much closer. It's a question of scalability, which means proportional increase in performance for a given increase in hardware capacity. With 4x the threads, work should proceed 4x faster.

So despite there being thousands of signatures in a given block, that's not nearly enough to saturate even a RPi5 with 4 cores, as you can see here: libbitcoin.org/sync.html#full…

What people miss when they make that assumption, is the spin up and down of of CPUs at the beginning and the end of each block. It creates a sawtooth CPU pattern, where most of the run the CPU is idle. bitcoind even reads ahead up to 1024 blocks, to prevent starvation, but even when the blocks are all present (reindex) there is significant starvation (shown on same link above).

The only way it scales is concurrent validation across large numbers of blocks. The chain will keep getting longer, and thread count will keep increasing. That scales, but only if you validation blocks in parallel. The amount of work in a single block never increases, and making that faster just asymptotically approaches something slightly faster than the bitcoind curve.

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Eric Voskuil Verified account @evoskuil · 2d

@reardencode This is not true, and I know your store far better than you do. The changes your clankers have made to our design have broken essential elements that were likely never fully understood.

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Eric Voskuil Verified account @evoskuil · 3d

How has bitcoind dominated the market for so long? Nobody has ever even matched its performance.

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