highperfocused/bitcoin
1
0
Fork 0
mirror of https://github.com/bitcoin/bitcoin.git synced 2026-01-20 23:29:12 +01:00
Code Issues Packages Projects Releases Wiki Activity

Use real number of cores for default -par, ignore virtual cores

Browse Source 
To determine the default for `-par`, the number of script verification
threads, use [boost::thread::physical_concurrency()](http://www.boost.org/doc/libs/1_58_0/doc/html/thread/thread_management.html#thread.thread_management.thread.physical_concurrency)
which counts only physical cores, not virtual cores.

Virtual cores are roughly a set of cached registers to avoid context
switches while threading, they cannot actually perform work, so spawning
a verification thread for them could even reduce efficiency and will put
undue load on the system.

Should fix issue #6358, as well as some other reported system overload
issues, especially on Intel processors.

The function was only introduced in boost 1.56, so provide a utility
function `GetNumCores` to fall back for older Boost versions.
This commit is contained in:
Wladimir J. van der Laan
2015-07-01 17:38:15 +02:00
parent da77a6f761
commit 47162673c7
5 changed files with 21 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
src/init.cpp
View File

@@ -283,7 +283,7 @@ std::string HelpMessage(HelpMessageMode mode)
strUsage += HelpMessageOpt("-loadblock=<file>", _("Imports blocks from external blk000??.dat file") + " " + _("on startup"));
strUsage += HelpMessageOpt("-maxorphantx=<n>", strprintf(_("Keep at most <n> unconnectable transactions in memory (default: %u)"), DEFAULT_MAX_ORPHAN_TRANSACTIONS));
strUsage += HelpMessageOpt("-par=<n>", strprintf(_("Set the number of script verification threads (%u to %d, 0 = auto, <0 = leave that many cores free, default: %d)"),
-(int)boost::thread::hardware_concurrency(), MAX_SCRIPTCHECK_THREADS, DEFAULT_SCRIPTCHECK_THREADS));
-GetNumCores(), MAX_SCRIPTCHECK_THREADS, DEFAULT_SCRIPTCHECK_THREADS));
#ifndef WIN32
strUsage += HelpMessageOpt("-pid=<file>", strprintf(_("Specify pid file (default: %s)"), "bitcoind.pid"));
#endif
@@ -774,7 +774,7 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
// -par=0 means autodetect, but nScriptCheckThreads==0 means no concurrency
nScriptCheckThreads = GetArg("-par", DEFAULT_SCRIPTCHECK_THREADS);
if (nScriptCheckThreads <= 0)
nScriptCheckThreads += boost::thread::hardware_concurrency();
nScriptCheckThreads += GetNumCores();
if (nScriptCheckThreads <= 1)
nScriptCheckThreads = 0;
else if (nScriptCheckThreads > MAX_SCRIPTCHECK_THREADS)