Ichthyostega
cd7581ba76
...even while this situation is unlikely, it needs to be considered: A worker thread might terminate unexpectedly, due to an error; all thread-local objects will be destroyed automatically — while the `EngineBufferManager` might be processing further allocations requested by that very thread, and dispatch them towards an already destroyed `LocalMemPool` This turns out to be a nasty problem, since the whole setup was created to allow the workers to operate independently from each other; any handshake or registration/deregistration mechanism would require a lock of sorts, thereby defeating the whole purpose of the setup. The best solution I could find is to rely on a instance marker hash, that can be checked with an atomic read prior to each dispatch of a memory allocation. The destructor of the local pool would then be able to ''disengage'', by invalidating that hash. To evaluate this solution, I developed this mechanism as a free-standing library component, called `LiveMark`
115 lines
2.9 KiB
C++
115 lines
2.9 KiB
C++
/*
|
||
THREAD.hpp - thin convenience wrapper for starting threads
|
||
|
||
Copyright (C)
|
||
2023, Hermann Vosseler <Ichthyostega@web.de>
|
||
|
||
**Lumiera** is free software; you can redistribute it and/or modify it
|
||
under the terms of the GNU General Public License as published by the
|
||
Free Software Foundation; either version 2 of the License, or (at your
|
||
option) any later version. See the file COPYING for further details.
|
||
|
||
* *****************************************************************/
|
||
|
||
/** @file thread.cpp
|
||
** This compilation unit holds some implementation details
|
||
** of the [thread wrapper](\ref lib::Thread), relegated here
|
||
** to reduce header inclusions.
|
||
** @warning setting the thread name only works on some POSIX systems,
|
||
** and using a GNU specific addition to the libC here.
|
||
*/
|
||
|
||
|
||
#include "lib/thread.hpp"
|
||
#include "lib/format-string.hpp"
|
||
#include "lib/symbol.hpp"
|
||
#include "lib/util.hpp"
|
||
|
||
#include <chrono>
|
||
#include <atomic>
|
||
#include <pthread.h>
|
||
|
||
using util::_Fmt;
|
||
using lib::Literal;
|
||
using std::atomic_uint;
|
||
using std::chrono::steady_clock;
|
||
using std::chrono_literals::operator ""ms;
|
||
|
||
|
||
|
||
namespace lib {
|
||
namespace thread{
|
||
|
||
namespace {
|
||
const auto SHUTDOWN_GRACE_PERIOD = 20ms;
|
||
|
||
string
|
||
lifecycleMsg (Literal phase, string threadID)
|
||
{
|
||
return _Fmt{"Thread '%s' %s"} % threadID % phase;
|
||
}
|
||
}
|
||
|
||
|
||
/** Helper to create a suffix to the thread-ID with running count */
|
||
string
|
||
ThreadWrapper::decorate_with_global_count (string const& rawID)
|
||
{
|
||
static atomic_uint globalCnt{1};
|
||
return _Fmt{"%s.%03i"} % rawID % globalCnt.fetch_add (+1, std::memory_order_relaxed);
|
||
}
|
||
|
||
|
||
/** @note implies get_id() != std::thread::id{} ==> it is running */
|
||
bool
|
||
ThreadWrapper::invokedWithinThread() const
|
||
{
|
||
return threadImpl_.get_id() == std::this_thread::get_id();
|
||
}
|
||
|
||
|
||
void
|
||
ThreadWrapper::markThreadStart()
|
||
{
|
||
TRACE (thread, "%s", lifecycleMsg ("start...", threadID_).c_str());
|
||
setThreadName();
|
||
}
|
||
|
||
|
||
void
|
||
ThreadWrapper::markThreadEnd()
|
||
{
|
||
TRACE (thread, "%s", lifecycleMsg ("terminates.", threadID_).c_str());
|
||
}
|
||
|
||
|
||
void
|
||
ThreadWrapper::setThreadName()
|
||
{
|
||
pthread_t nativeHandle = threadImpl_.native_handle();
|
||
|
||
// API limitation: max 15 characters + \0
|
||
pthread_setname_np(nativeHandle, threadID_.substr(0, 15).c_str());
|
||
}
|
||
|
||
|
||
void
|
||
ThreadWrapper::waitGracePeriod() noexcept
|
||
{
|
||
try {
|
||
auto start = steady_clock::now();
|
||
while (threadImpl_.joinable()
|
||
and steady_clock::now () - start < SHUTDOWN_GRACE_PERIOD
|
||
)
|
||
std::this_thread::yield();
|
||
}
|
||
ERROR_LOG_AND_IGNORE (thread, lifecycleMsg("shutdown wait", threadID_).c_str());
|
||
|
||
if (threadImpl_.joinable())
|
||
ALERT (thread, "Thread '%s' failed to terminate after grace period. Abort.", threadID_.c_str());
|
||
// invocation of std::thread dtor will presumably call std::terminate...
|
||
}
|
||
|
||
|
||
|
||
}}// namespace lib::thread
|