Why is creating a new process more expensive on Windows than Linux?

by

mweerden: NT has been designed for multi-user from day one, so this is not really a reason. However, you are right about that process creation plays a less important role on NT than on Unix as NT, in contrast to Unix, favors multithreading over multiprocessing.

Rob, it is true that fork is relatively cheap when COW is used, but as a matter of fact, fork is mostly followed by an exec. And an exec has to load all images as well. Discussing the performance of fork therefore is only part of the truth.

When discussing the speed of process creation, it is probably a good idea to distinguish between NT and Windows/Win32. As far as NT (i.e. the kernel itself) goes, I do not think process creation (NtCreateProcess) and thread creation (NtCreateThread) is significantly slower as on the average Unix. There might be a little bit more going on, but I do not see the primary reason for the performance difference here.

If you look at Win32, however, you’ll notice that it adds quite a bit of overhead to process creation. For one, it requires the CSRSS to be notified about process creation, which involves LPC. It requires at least kernel32 to be loaded additionally, and it has to perform a number of additional bookkeeping work items to be done before the process is considered to be a full-fledged Win32 process. And let’s not forget about all the additional overhead imposed by parsing manifests, checking if the image requires a compatbility shim, checking whether software restriction policies apply, yada yada.

That said, I see the overall slowdown in the sum of all those little things that have to be done in addition to the raw creation of a process, VA space, and initial thread. But as said in the beginning — due to the favoring of multithreading over multitasking, the only software that is seriously affected by this additional expense is poorly ported Unix software. Although this sitatuion changes when software like Chrome and IE8 suddenly rediscover the benefits of multiprocessing and begin to frequently start up and teardown processes…

More Related Contents:

  1. What characters are forbidden in Windows and Linux directory names?
  2. NTFS performance and large volumes of files and directories
  3. How can I determine whether a specific file is open in Windows? [closed]
  4. How to convert Windows end of line in Unix end of line (CR/LF to LF)
  5. What is the difference between mutex and critical section?
  6. System Calls in windows & Native API?
  7. How to get 100% CPU usage from a C program
  8. Concurrency in a GIT repo on a network shared folder
  9. ^M at the end of every line in vim
  10. Does Windows have Inode Numbers like Linux?
  11. Variables are not behaving as expected
  12. How to stop java process gracefully?
  13. what’s the differences between r and rb in fopen
  14. Windows batch script to parse CSV file and output a text file
  15. Using parameters in batch files at Windows command line
  16. Faking an RS232 Serial Port
  17. How to run a command on command prompt startup in Windows
  18. ETIMEDOUT Error while installing Node packages on Windows
  19. Command line to remove an environment variable from the OS level configuration
  20. How to open an elevated cmd using command line for Windows?
  21. How to upgrade Git on Windows to the latest version
  22. windows – How to enumerate all connected USB devices’ device path?
  23. Git Bash doesn’t see my PATH
  24. How to test if a path is a file or directory in Windows batch file?
  25. driver.manage().window().maximize() issue with ChromeDriver 2.33
  26. Access a localhost running in Windows from inside WSL2? [closed]
  27. Find absolute java.exe path programmatically from java code
  28. create process in user session from service
  29. How do I remove the process currently using a port on localhost in Windows? [closed]
  30. How to change the build type to Release mode in cmake?

Leave a Comment