Max number of threads per process windows

Ideally you will be using APIs that use IO completion ports so a thread is not comsumed while the IO is taking place but even if not you can dispatch a whole series of IO bound requests on separate threads so the IO is taking place concurrently. Each thread is going to incur overhead in terms of memory and scheduling.

Each thread has resources including a default of a 1Mb stack. So on 32 bit CLR you have a hard limit around threads. However, by this time you will have swamped the thread scheduler in so much work that your application will spend most of its time thrashing around switching threads.

Thursday, February 26, AM. Make as many as you like up to int. Only one thread per core will be active. Making more than one per core slows down processing. I removed all the 'new' heap allocations and replaced them with stack based allocations.

This simplifies the code and makes cleanup easier. Usually you want to use heap based allocations when creating a thread to ensure the params don't go out of scope while the thread is executing. In this case, we ensure that we aren't going out of scope prematurely because we are waiting on both child events. This code seems to work fine with deltaX at 0. On my machine the max threads seem to peak at about which is better than the default QUWI thread pool count and much better than the nt max thread count.

Arjay Code:. May 3rd, , AM Originally Posted by raindog. Attached Files ThreadPool. Did you add the following to the top of your includes? See the attachment for the complete solution. Re: What is the maximum number of threads per process in Windows i'm a bit new to all this what does ::CloseHandle instead of CloseHandle mean? Page 1 of 3 1 2 3 Last Jump to page:. NET Framework. How hard would it really be to port to Windows 8? All times are GMT The time now is AM.

Copyright TechnologyAdvice. CodeGuru Home. Visual Basic. VB Forums. You may have to register or Login before you can post: click the register link above to proceed. The Executive allocates handle tables on demand in page-sized blocks that it divides into handle table entries.

That means a page, which is bytes on both x86 and x64, can store entries on bit Windows and entries on bit Windows. The Executive determines the maximum number of pages to allocate for handle entries by dividing the hard-coded maximum,16,,, by the number of handle entries in a page, which results on bit Windows to 32, and on bit Windows to 65, Because the Executive uses the first entry of each page for its own tracking information, the number of handles available to a process is actually 16,, minus those numbers, which explains the results obtained by Testlimit: 16,,, is 16,, and 16,,,, is 16,, The second limit affecting handles is the amount of memory required to store handle tables, which the Executive allocates from paged pool.

The Executive uses a three-level scheme, similar to the way that processor Memory Management Units MMUs manage virtual to physical address translations, to keep track of the handle table pages that it allocates. The top level serves as pointers into the mid-level tables and includes entries per-page on bit Windows. On bit Windows, there are pointers in a page of top-level pointers.

A handle leaker will have a handle count that rises over time. The reason that a handle leak is so insidious is that unlike the handles Testlimit creates, which all point to the same object, a process leaking handles is probably leaking objects as well.

For example, if a process creates events but fails to close them, it will leak both handle entries and event objects.

Event objects consume nonpaged pool, so the leak will impact nonpaged pool in addition to paged pool. If you spot a leak in a process that can host multiple components or extensions, like Explorer, a Service Host or Internet Explorer, then the question is what component is the one responsible for the leak. Figuring that out might enable you to avoid the problem by disabling or uninstalling the problematic extension, fix the problem by checking for an update, or report the bug to the vendor.

Fortunately, Windows includes a handle tracing facility that you can use to help identify leaks and the responsible software. You can enable it either by using the Application Verifier , a free download from Microsoft, or by using the Windows D ebugger Windbg.

To demonstrate the tracing in action, I launched Windbg and attached to the Command Prompt I had opened earlier.