Lecture 2 Processes and Threads
... So DOS and other uniprogrammed systems put in things like memory-resident programs that invoked asynchronously, but still have separation problems. One key problem with DOS is that there is no memory protection - one program may write the memory of another program, causing weird bugs. ...
... So DOS and other uniprogrammed systems put in things like memory-resident programs that invoked asynchronously, but still have separation problems. One key problem with DOS is that there is no memory protection - one program may write the memory of another program, causing weird bugs. ...
3.5 Interprocess Communication
... 5. We have seen two concepts: process and thread What is in common between the two concepts? What is different between the two concepts? ...
... 5. We have seen two concepts: process and thread What is in common between the two concepts? What is different between the two concepts? ...
Threads
... Save context of processor including program counter and other registers Update the PCB of the running process with its new state and other associate info Move PCB to appropriate queue - ready, ...
... Save context of processor including program counter and other registers Update the PCB of the running process with its new state and other associate info Move PCB to appropriate queue - ready, ...
No Slide Title - ECE Users Pages
... CPU moves data from/to main memory to/from local buffers I/O is from the device to local buffer of controller. Device controller informs CPU that it has finished its operation by causing an interrupt. Interrupt transfers control to the interrupt service routine generally, through the interrupt vecto ...
... CPU moves data from/to main memory to/from local buffers I/O is from the device to local buffer of controller. Device controller informs CPU that it has finished its operation by causing an interrupt. Interrupt transfers control to the interrupt service routine generally, through the interrupt vecto ...
ppt
... • But, they’re still pretty expensive for fine-grained use – orders of magnitude more expensive than a procedure call – thread operations are all system calls • context switch • argument checks © 2013 Gribble, Lazowska, Levy, Zahorjan ...
... • But, they’re still pretty expensive for fine-grained use – orders of magnitude more expensive than a procedure call – thread operations are all system calls • context switch • argument checks © 2013 Gribble, Lazowska, Levy, Zahorjan ...
address space
... • The OS is a huge multi-threaded program. • Multi-threading is useful for applications as well. • User-Level threads can be 100x faster than similar kernel thread operations. • But user-leve threads suffer from a problem of poor integration; because they’re invisible to the OS, the OS can make poor ...
... • The OS is a huge multi-threaded program. • Multi-threading is useful for applications as well. • User-Level threads can be 100x faster than similar kernel thread operations. • But user-leve threads suffer from a problem of poor integration; because they’re invisible to the OS, the OS can make poor ...
Communication - Computer Science Division
... – Inter-thread communication cheap: can use process memory and may not need to context switch – Not secure: a thread can write the memory used by another thread ...
... – Inter-thread communication cheap: can use process memory and may not need to context switch – Not secure: a thread can write the memory used by another thread ...
L11-thread-impl
... – No ,mer to make a thread yield the CPU – Threads must voluntarily yield control to let another thread run, e.g., pthread_yield() – Thread history isn’t taken into account by scheduler – Threads are ...
... – No ,mer to make a thread yield the CPU – Threads must voluntarily yield control to let another thread run, e.g., pthread_yield() – Thread history isn’t taken into account by scheduler – Threads are ...
THE MACH SYSTEM
... Task: Execution environment Contains one or more threads Provides a protection domain, a protected access to system resources via ports Thread: unit of computation (execution) must run in the context of a task all threads in a task share ports, memory, etc. process = task + thread ...
... Task: Execution environment Contains one or more threads Provides a protection domain, a protected access to system resources via ports Thread: unit of computation (execution) must run in the context of a task all threads in a task share ports, memory, etc. process = task + thread ...
Slides for week 3
... Create an exact clone of the calling process After the call, two processes: parent (the calling process) and child (the process created) ...
... Create an exact clone of the calling process After the call, two processes: parent (the calling process) and child (the process created) ...
PPT
... To make threads really fast, they should be implemented at the user level A user-level thread is managed entirely by the run-time system (user-level code that is linked with your program). Each thread is represented simply by a PC, registers, stack and a little control block, managed in the user’s a ...
... To make threads really fast, they should be implemented at the user level A user-level thread is managed entirely by the run-time system (user-level code that is linked with your program). Each thread is represented simply by a PC, registers, stack and a little control block, managed in the user’s a ...
threads
... Allow an interactive program to continue running even if part of it is blocked or is performing a lengthy operation ...
... Allow an interactive program to continue running even if part of it is blocked or is performing a lengthy operation ...
An all-in-one monolithic kernel.
... • Blocking threads don’t stop the entire process. • Threads from the same process can run simultaneously on different cores/processors. • Switching between threads is faster. ...
... • Blocking threads don’t stop the entire process. • Threads from the same process can run simultaneously on different cores/processors. • Switching between threads is faster. ...
Lecture OS - University of Wisconsin
... between threads, and synchronization between threads can all be done without intervention of the kernel fast — thread switching is not much more expensive than a procedure call flexible — CPU scheduling (among those threads) can be customized to suit the needs of the algorithm ...
... between threads, and synchronization between threads can all be done without intervention of the kernel fast — thread switching is not much more expensive than a procedure call flexible — CPU scheduling (among those threads) can be customized to suit the needs of the algorithm ...
sample PPT 2 - Virginia Tech
... Compatible with POSIX application code Good Performance due to fast interdomain communication ...
... Compatible with POSIX application code Good Performance due to fast interdomain communication ...
Slide 1
... the process i.e. handles, one or more threads • Threads are the units of execution – they execute program code using the processes context and resources ...
... the process i.e. handles, one or more threads • Threads are the units of execution – they execute program code using the processes context and resources ...
slides
... Multithreading Models (cont’d) In multithreaded kernels (i.e., most current OSs), mapping from ...
... Multithreading Models (cont’d) In multithreaded kernels (i.e., most current OSs), mapping from ...
Power Point XP
... If time slice expires, lower the priority by one level If time slice does not expire, raise the priority by one level ...
... If time slice expires, lower the priority by one level If time slice does not expire, raise the priority by one level ...
Shared Address Space Computing: Programming Fork/Join
... – Applications can be developed on serial machine and run on parallel machines without changes (is this really true?) ...
... – Applications can be developed on serial machine and run on parallel machines without changes (is this really true?) ...
1up
... – Applications can be developed on serial machine and run on parallel machines without changes (is this really true?) ...
... – Applications can be developed on serial machine and run on parallel machines without changes (is this really true?) ...
Power Point XP - FSU Computer Science
... Kernel needs to notify the thread system of various events (e.g., blocking) via upcalls Kernel needs to make a kernel thread available to activate user-level scheduler ...
... Kernel needs to notify the thread system of various events (e.g., blocking) via upcalls Kernel needs to make a kernel thread available to activate user-level scheduler ...
Figure 5.01
... Both M:M and Two-level models require communication to maintain the appropriate number of kernel threads allocated to the application Scheduler activations provide upcalls - a communication mechanism from the kernel to the thread library ...
... Both M:M and Two-level models require communication to maintain the appropriate number of kernel threads allocated to the application Scheduler activations provide upcalls - a communication mechanism from the kernel to the thread library ...
Thread (computing)
In computer science, a thread of execution is the smallest sequence of programmed instructions that can be managed independently by a scheduler, which is typically a part of the operating system. The implementation of threads and processes differs between operating systems, but in most cases a thread is a component of a process. Multiple threads can exist within the same process, executing concurrently (one starting before others finish) and share resources such as memory, while different processes do not share these resources. In particular, the threads of a process share its instructions (executable code) and its context (the values of its variables at any given moment).On a single processor, multithreading is generally implemented by time slicing (as in multitasking), and the central processing unit (CPU) switches between different software threads. This context switching generally happens frequently enough that the user perceives the threads or tasks as running at the same time (in parallel). On a multiprocessor or multi-core system, multiple threads can be executed in parallel (at the same instant), with every processor or core executing a separate thread simultaneously; on a processor or core with hardware threads, separate software threads can also be executed concurrently by separate hardware threads.Threads made an early appearance in OS/360 Multiprogramming with a Variable Number of Tasks (MVT) in 1967, in which they were called ""tasks"". Process schedulers of many modern operating systems directly support both time-sliced and multiprocessor threading, and the operating system kernel allows programmers to manipulate threads by exposing required functionality through the system call interface. Some threading implementations are called kernel threads, whereas lightweight processes (LWP) are a specific type of kernel thread that share the same state and information. Furthermore, programs can have user-space threads when threading with timers, signals, or other methods to interrupt their own execution, performing a sort of ad hoc time-slicing.