Since block validation happens in parallel, multiple threads may be
accessing the signature cache simultaneously. To prevent contention:
* Turn the signature cache lock into a shared mutex
* Make reading from the cache only acquire a shared lock
* Let block validations not store their results in the cache
* During block verification (when parallelism is requested), script
check actions are stored instead of being executed immediately.
* After every processed transactions, its signature actions are
pushed to a CScriptCheckQueue, which maintains a queue and some
synchronization mechanism.
* Two or more threads (if enabled) start processing elements from
this queue,
* When the block connection code is finished processing transactions,
it joins the worker pool until the queue is empty.
As cs_main is held the entire time, and all verification must be
finished before the block continues processing, this does not reach
the best possible performance. It is a less drastic change than
some more advanced mechanisms (like doing verification out-of-band
entirely, and rolling back blocks when a failure is detected).
The -par=N flag controls the number of threads (1-16). 0 means auto,
and is the default.
- ensure we use strCaption for printf and fprintf, as before it could
happen to have an error message in the debug.log, which had no "Error"
(or whatever) in front
- this prevents an interference with the IPC message queue (which is used
for URI processing) when running a testnet and mainnet instance in
parallel
- to check for testnet, I had to raise the ParseParameters() call in
main() to the topmost position
- a click on "Reset Options" sets all options to the default values by
removing all stored settings (QSettings), loading the defaults and
saving them as the new settings
- before the reset is executed the user is presented a confirmation dialog
- special casing was needed for StartAtStartup
- some users reported it as weird, that the estimated block count could be
lower than our own nodes block number (which is indeed true and not good)
- this pull adds a new default behaviour, which displays our own block
number as estimated block number, if own >= est. block count
- the pull raises space for nodes block counts in cPeerBlockCounts to 8 to
be more accurate
- also removes a reduntant setNumBlocks() call in RPCConsole and moves
initialisation of numBlocksAtStartup in ClientModel, where it belongs
