Changeset deeda09 for doc/theses/colby_parsons_MMAth/text
- Timestamp:
- Apr 4, 2023, 11:58:50 AM (2 years ago)
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TabularUnified doc/theses/colby_parsons_MMAth/text/CFA_concurrency.tex ¶
r11e3e97 rdeeda09 1 1 \chapter{Concurrency in \CFA}\label{s:cfa_concurrency} 2 2 3 The groundwork for concurrency in \CFA was laid by Thierry Delisle in his Master's Thesis \cite{Delisle18}.4 In that work he introduced coroutines, user level threading, and monitors.5 Not listed in that work were the other concurrency features that were needed as building blocks, such as locks, futures, and condition variableswhich he also added to \CFA.3 The groundwork for concurrency in \CFA was laid by Thierry Delisle in his Master's Thesis~\cite{Delisle18}. 4 In that work, he introduced generators, coroutines, monitors, and user-level threading. 5 Not listed in that work were basic concurrency features needed as building blocks, such as locks, futures, and condition variables, which he also added to \CFA. 6 6 7 7 \section{Threading Model}\label{s:threading} 8 \CFA has user level threading and supports a $M:N$ threading model where $M$ user threads are scheduled on $N$ cores, where both $M$ and $N$ can be explicitly set by the user. 9 Cores are used by a program by creating instances of a \code{processor} struct. 10 User threads types are defined using the \code{thread} keyword, in the place where a \code{struct} keyword is typically used. 11 For each thread type a corresponding main must be defined, which is where the thread starts running once it is created. 12 Listing~\ref{l:cfa_thd_init} shows an example of processor and thread creation. 13 When processors are added, they are added alongside the existing processor given to each program. 14 Thus if you want $N$ processors you need to allocate $N-1$. 15 To join a thread the thread must be deallocated, either deleted if it is allocated on the heap, or go out of scope if stack allocated. 16 The thread performing the deallocation will wait for the thread being deallocated to terminate before the deallocation can occur. 17 A thread terminates by returning from the main routine where it starts. 8 \CFA provides user-level threading and supports an $M$:$N$ threading model where $M$ user threads are scheduled on $N$ kernel threads, where both $M$ and $N$ can be explicitly set by the user. 9 Kernel threads are created by instancing a @processor@ structure. 10 User-thread types are defined by creating a @thread@ aggregate-type, \ie replace @struct@ with @thread@. 11 For each thread type a corresponding @main@ routine must be defined, which is where the thread starts running once it is created. 12 Examples of \CFA user thread and processor creation are shown in \VRef[Listing]{l:cfa_thd_init}. 18 13 19 \begin{cfa}[tabsize=3,caption={\CFA user thread and processor creation},label={l:cfa_thd_init}] 20 21 thread my_thread {} // user thread type 22 void main( my_thread & this ) { // thread start routine 23 printf("Hello threading world\n"); 14 \begin{cfa}[caption={Example of \CFA user thread and processor creation},label={l:cfa_thd_init}] 15 @thread@ my_thread {...}; $\C{// user thread type}$ 16 void @main@( my_thread & this ) { $\C{// thread start routine}$ 17 sout | "Hello threading world"; 24 18 } 25 19 26 20 int main() { 27 // add 2 processors, now 3 total 28 processor p[2]; 29 { 30 my_thread t1; 31 my_thread t2; 32 } // waits for threads to end before going out of scope21 processor p[2]; $\C{// add 2 processors = 3 total with starting processor}$ 22 { 23 my_thread t[2], * t3 = new(); $\C{// create 3 user threads, running in main routine}$ 24 ... // execute concurrently 25 delete( t3 ); $\C{// wait for thread to end and deallocate}$ 26 } // waits for threads to end and deallocate 33 27 } 28 \end{cfa} 34 29 35 \end{cfa} 30 When processors are added, they are added alongside the existing processor given to each program. 31 Thus, for $N$ processors, allocate $N-1$ processors. 32 A thread is implicitly joined at deallocated, either implicitly at block exit for stack allocation or explicitly at @delete@ for heap allocation. 33 The thread performing the deallocation must wait for the thread to terminate before the deallocation can occur. 34 A thread terminates by returning from the main routine where it starts. 35 36 % Local Variables: % 37 % tab-width: 4 % 38 % End: %
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