Merge #15849: Thread names in logs and deadlock debug tools

8722e54e56 threads: add thread names to deadlock debugging message (James O'Beirne)
383b186c28 threads: prefix log messages with thread names (James O'Beirne)
ddd95ccb80 tests: add threadutil tests (James O'Beirne)
ae5f2b6a6c threads: introduce util/threadnames, refactor thread naming (James O'Beirne)
188ca75e5f disable HAVE_THREAD_LOCAL on unreliable platforms (James O'Beirne)

Pull request description:

  I'm resurrecting this one (from #13168) because I need it to make progress on #15735.

  It's now off by default and can be turned on with `-logthreadnames=1`.

  Ran some benchmarks (IBD from local peer from 500_000 -> 504_000) and it's within spitting distance either on or off:

  ### threadnames off (default)

  #### 2018-05-threadnames.3 vs. master (absolute)
  |                      name                      | iterations |   2018-05-threadnames.3    |           master           |
  |------------------------------------------------|-----------:|----------------------------|----------------------------|
  | ibd.local.500000.504000.dbcache=2048           |          3 | 376.1584 (± 9.2944)        | 392.3414 (± 13.4238)       |
  | ibd.local.500000.504000.dbcache=2048.mem-usage |          3 | 2236117.3333 (± 1845.9623) | 2238690.6667 (± 2669.3487) |

  #### 2018-05-threadnames.3 vs. master (relative)
  |                      name                      | iterations | 2018-05-threadnames.3 | master |
  |------------------------------------------------|-----------:|----------------------:|-------:|
  | ibd.local.500000.504000.dbcache=2048           |          3 |                     1 |  1.043 |
  | ibd.local.500000.504000.dbcache=2048.mem-usage |          3 |                     1 |  1.001 |

  ### threadnames on

  #### 2018-05-threadnames-take-2 vs. master (absolute)
  |                      name                      | iterations | 2018-05-threadnames-take-2 |           master           |
  |------------------------------------------------|-----------:|----------------------------|----------------------------|
  | ibd.local.500000.504000.dbcache=2048           |          3 | 367.6861 (± 0.3941)        | 364.1667 (± 0.9776)        |
  | ibd.local.500000.504000.dbcache=2048.mem-usage |          3 | 2238461.3333 (± 3697.8730) | 2237014.6667 (± 3307.6966) |

  #### 2018-05-threadnames-take-2 vs. master (relative)
  |                      name                      | iterations | 2018-05-threadnames-take-2 | master |
  |------------------------------------------------|-----------:|---------------------------:|-------:|
  | ibd.local.500000.504000.dbcache=2048           |          3 |                      1.010 |   1.00 |
  | ibd.local.500000.504000.dbcache=2048.mem-usage |          3 |                      1.001 |   1.00 |
  ```

ACKs for commit 8722e5:
  Empact:
    utACK https://github.com/bitcoin/bitcoin/pull/15849/commits/8722e54e56fd959fd4ff2321b36a7640dee440c5
  jnewbery:
    utACK 8722e54e56fd959fd4ff2321b36a7640dee440c5
  MarcoFalke:
    re-utACK 8722e54e56fd959fd4ff2321b36a7640dee440c5 (Only change since my previous review is DEFAULT_LOGTHREADNAMES=false and stylistic updates

Tree-SHA512: 50af992708295b8d680cf10025262dd964e599a356bdfc1dfc84fb18c00afabcb34d3d12d551b0677ff81f8fccad0e17c1d5b24dfecb953a913bc77fdd1a4577

1 files changed, 19 insertions, 10 deletions

diff --git a/src/sync.cpp b/src/sync.cpp
index 23ca866e5..e7c0a6f9b 100644
--- a/src/sync.cpp
+++ b/src/sync.cpp
@@ -3,9 +3,11 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <sync.h>
+#include <tinyformat.h>
 
 #include <logging.h>
 #include <util/strencodings.h>
+#include <util/threadnames.h>
 
 #include <stdio.h>
 
@@ -37,23 +39,30 @@ void PrintLockContention(const char* pszName, const char* pszFile, int nLine)
 //
 
 struct CLockLocation {
-    CLockLocation(const char* pszName, const char* pszFile, int nLine, bool fTryIn)
-    {
-        mutexName = pszName;
-        sourceFile = pszFile;
-        sourceLine = nLine;
-        fTry = fTryIn;
-    }
+    CLockLocation(
+        const char* pszName,
+        const char* pszFile,
+        int nLine,
+        bool fTryIn,
+        const std::string& thread_name)
+        : fTry(fTryIn),
+          mutexName(pszName),
+          sourceFile(pszFile),
+          m_thread_name(thread_name),
+          sourceLine(nLine) {}
 
     std::string ToString() const
     {
-        return mutexName + "  " + sourceFile + ":" + itostr(sourceLine) + (fTry ? " (TRY)" : "");
+        return tfm::format(
+            "%s %s:%s%s (in thread %s)",
+            mutexName, sourceFile, itostr(sourceLine), (fTry ? " (TRY)" : ""), m_thread_name);
     }
 
 private:
     bool fTry;
     std::string mutexName;
     std::string sourceFile;
+    const std::string& m_thread_name;
     int sourceLine;
 };
 
@@ -125,7 +134,7 @@ static void push_lock(void* c, const CLockLocation& locklocation)
         std::pair<void*, void*> p1 = std::make_pair(i.first, c);
         if (lockdata.lockorders.count(p1))
             continue;
-        lockdata.lockorders[p1] = g_lockstack;
+        lockdata.lockorders.emplace(p1, g_lockstack);
 
         std::pair<void*, void*> p2 = std::make_pair(c, i.first);
         lockdata.invlockorders.insert(p2);
@@ -141,7 +150,7 @@ static void pop_lock()
 
 void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry)
 {
-    push_lock(cs, CLockLocation(pszName, pszFile, nLine, fTry));
+    push_lock(cs, CLockLocation(pszName, pszFile, nLine, fTry, util::ThreadGetInternalName()));
 }
 
 void LeaveCritical()