## A Multithreaded, Transaction-Based Locking Strategy for Containers Bob Steagall CppCon 2020 KEWB COMPUTING ## Overview • Sharing a container among multiple threads • A motivating problem • Some

|000|000|00000||| ## Persistence Goal: Add persistence to concurrent data structures Leverage existing multithreaded synchronization guarantees |Introduction|Persistent Hash Map|Persistent Transactional Data Structures|Live |000|000|00000||| ## Persistence Goal: Add persistence to concurrent data structures Leverage existing multithreaded synchronization guarantees Naive idea: flush-on-read [15] Flush newly created objects (ex. node |000|000|00000||| ## Persistence Goal: Add persistence to concurrent data structures Leverage existing multithreaded synchronization guarantees Naive idea: flush-on-read [15] ▶ Flush newly created objects (ex

when you call CreateDevice or CreateDeviceEx to create a device, you can specify the D3DCREATE_MULTITHREADED flag to make the Direct3D 9 API thread safe. This causes significant synchronization overhead Consoles being ahead in tech? Madness! ## Redesigning for multithread Switching to DX11 allows for multithreaded texture and model loaded Loading algorithms needed to be rewritten 2D and 3D asset loading needed

(P0493) ## Atomic min/max motivation (P0493) Long history - almost as old as atomic addition Multithreaded applications often involve scenarios where multiple threads need to concurrently update a shared concurrent updates to shared variables, facilitating the development of high-performance and scalable multithreaded applications. - By understanding the semantics and proper usage of atomic min/max, you can leverage

some platform-specific library, such as pthreads. But then what could the Standard say about multithreaded programs? |Thread A|Thread B| |---|---| |int x = 0;|| |start\_thread\_b();|while (x != 1) {}| gives us “counting” primitives like semaphore and latch - But if your program is fundamentally multithreaded, look for higher-level facilities: promise/future, coroutines, ASIO, TBB Questions? followed

Threading M application threads -> N hardware threads The same distinctions can be done at a multithreaded language or multithreading runtime level. ## The problem ## How to schedule M tasks on N hardware on cactus stacks / segmented stacks https://github.com/mratsim/weave/blob/v0.3.0/weave/memory/multithreaded_memory_management.md - Plagued Go and Rust (abandoned) - Decades of research including OS kernel

memtable_flush_queue_size 73 memtable_flush_writers 73 memtable_total_space_in_mb 73 multithreaded_compaction 73 reduce_cache_capacity_to 73 reduce_cache_sizes_at 73 sliced_buffer_size_in_kb ace\_in\_ms|Re-no86 (replaces column family storage property memtable\_flush\_after\_mins)| |multithreaded\_compaction|false| |memtable\_total\_space\_in\_ms|Re-of heap (replaces column family storage |memtable\_flush\_writers|One per data directory| |memtable\_total\_space\_in\_mb|1/3 of the heap| |multithreaded\_compaction|false| |partitioner|org.apache.Cassandra.dht.RandomPartitioner| |phi\_convict\_threshold|8|

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 547 3 Final Project: Building a Multithreaded Web Server 551 3.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553 3.2 . single-threaded scenarios; the next chapter on concurrency will cover how to do reference counting in multithreaded programs. If you try to use Rc with multiple threads, you’ll get a compile-time error. Using functionality of RefCell in a multithreaded program in the next chapter on concurrency. For now, all you need to know is that if you try to use RefCell in a multithreaded context, you’ll get a compile

runtime 函数库于1970s 年代产生出来时，PC 的内存容量还很小，多任务是 个新奇观念，更别提什么多执行线程了。因此以当时产品为基础所演化的C runtime 函 数库在多线程（multithreaded）的表现上有严重问题，无法被多线程程序使用。 利用各种同步机制（synchronous mechanism）如critical section、mutex、semaphore、 event c） libc.lib 898,826 Multithreaded（static） libcmt.lib 951,142 Multithreaded DLL msvcrt.lib 5,510,000 Debug Single-Threaded（static） libcd.lib 2,374,542 Debug Multithreaded（static）libcmtd.lib 2,949 949,190 Debug Multithreaded DLL msvcrtd.lib 803,418 Visual C++ 编译器提供下列选项，让我们决定使用哪一个C runtime 函数库： /ML Single-Threaded（static） /MT Multithreaded（static） /MD Multithreaded DLL（dynamic import library）

Collection Overview 445 35.2 Memory Architecture 445 35.3 System Memory Requirements 446 35.4 Multithreaded Garbage Collection 446 35.5 Monitoring and Debugging 447 35.6 Performance Considerations 448 35 incorrect results and dangerous errors. Lets say we want to make the function sum_single below multithreaded. julia> function sum_single(a) s = 0 for i in a s += i end s via the JULIA_HEAP_SIZE_HINT environment variable: export JULIA_HEAP_SIZE_HINT=2G julia 35.4 Multithreaded Garbage Collection Julia’s garbage collector can leverage multiple threads to improve performance