Parallelize script verification

* 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.
This commit is contained in:
Pieter Wuille
2012-12-01 23:04:14 +01:00
parent 1d70f4bde8
commit f9cae832e6
7 changed files with 281 additions and 6 deletions

View File

@@ -84,6 +84,10 @@ void Shutdown(void* parg)
fShutdown = true;
nTransactionsUpdated++;
bitdb.Flush(false);
{
LOCK(cs_main);
ThreadScriptCheckQuit();
}
StopNode();
{
LOCK(cs_main);
@@ -303,6 +307,7 @@ std::string HelpMessage()
" -checklevel=<n> " + _("How thorough the block verification is (0-6, default: 1)") + "\n" +
" -loadblock=<file> " + _("Imports blocks from external blk000??.dat file") + "\n" +
" -reindex " + _("Rebuild blockchain index from current blk000??.dat files") + "\n" +
" -par=N " + _("Set the number of script verification threads (1-16, 0=auto, default: 0)") + "\n" +
"\n" + _("Block creation options:") + "\n" +
" -blockminsize=<n> " + _("Set minimum block size in bytes (default: 0)") + "\n" +
@@ -484,6 +489,15 @@ bool AppInit2()
fDebug = GetBoolArg("-debug");
fBenchmark = GetBoolArg("-benchmark");
// -par=0 means autodetect, but nScriptCheckThreads==0 means no concurrency
nScriptCheckThreads = GetArg("-par", 0);
if (nScriptCheckThreads == 0)
nScriptCheckThreads = boost::thread::hardware_concurrency();
if (nScriptCheckThreads <= 1)
nScriptCheckThreads = 0;
else if (nScriptCheckThreads > MAX_SCRIPTCHECK_THREADS)
nScriptCheckThreads = MAX_SCRIPTCHECK_THREADS;
// -debug implies fDebug*
if (fDebug)
fDebugNet = true;
@@ -579,6 +593,12 @@ bool AppInit2()
if (fDaemon)
fprintf(stdout, "Bitcoin server starting\n");
if (nScriptCheckThreads) {
printf("Using %u threads for script verification\n", nScriptCheckThreads);
for (int i=0; i<nScriptCheckThreads-1; i++)
NewThread(ThreadScriptCheck, NULL);
}
int64 nStart;
// ********************************************************* Step 5: verify database integrity