What functions take up most of the time for a new or restored simplewallet?

Is it the scanning for its own inputs?

What code line does the most heavy lifting in the simplewallet codebase?

Lets say I restore a wallet from a block 14 days ago, what checks are performed, after I get all the blocks and pruned tx data, that take most of the time.

2 Answers 2


The two main operations in terms of CPU usage are determining if an output is sent to you (is_out_to_acc_precomp, defined in src/cryptonote_basic/cryptonote_format_utils.cpp) and generating the key derivations that is_out_to_acc_precomp acts on (generate_key_derivation, defined in src/crypto/crypto.cpp). There is some threading there, but it could still be sped up.

Both of those end up calling low level crypto functions, such that a profile looks like this:

  18.00%  monero-wallet-cli          [.] fe_sq
  17.54%  monero-wallet-cli          [.] fe_cmov
   3.21%  monero-wallet-cli          [.] fe_invert
   3.08%  monero-wallet-cli          [.] fe_divpowm1
   2.86%  monero-wallet-cli          [.] fe_sq2
   2.35%  monero-wallet-cli          [.] fe_add
   1.75%  monero-wallet-cli          [.] select
   1.62%  monero-wallet-cli          [.] keccakf
   1.16%  monero-wallet-cli          [.] ge_p2_dbl
   0.97%  monero-wallet-cli          [.] ge_scalarmult_base
   0.80%  monero-wallet-cli          [.] ge_scalarmult

There are a couple asm versions of those, which proved to give some substantial speedup too, see https://github.com/monero-project/monero/pull/2317


Without profiling, I would guess void wallet2::process_new_transaction (link) or by virtue of it being called, one of it's ancestors. This is because an incoming block has to have it's transactions scanned.

Of course, only profiling can confirm this guess.

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