| msg71289 - (view) |
Author: Kristján Valur Jónsson (kristjan.jonsson) *  |
Date: 2008-08-17 21:00 |
| Here is a suggested update to thread_nt.c. It has two significant changes: 1) it uses the new and safer _beginthreadex API to start a thread 2) it implements native TLS functions on NT, which are certain to be as fast as possible. |
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| msg79179 - (view) |
Author: Amaury Forgeot d'Arc (amaury.forgeotdarc) * |
Date: 2009-01-05 18:12 |
| - Isn't CreateThread even better? - Using TLS functions is a good idea, beware though that the number of TLS slots cannot exceed 1088 on Windows. This should at least be documented. OTOH since there is only one call to PyThread_create_key in the codebase (for the GIL), and I found only one more through the Google Code Search, it's probably not worth the trouble. |
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| msg79180 - (view) |
Author: Ulrich Eckhardt (eckhardt) |
Date: 2009-01-05 18:25 |
| No, CreateThread() is not a suitable replacement, because it lacks some initialisations of the C library, as explained in the MSDN: http://msdn.microsoft.com/en-us/library/ms682453(VS.85).aspx |
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| msg79188 - (view) |
Author: Amaury Forgeot d'Arc (amaury.forgeotdarc) * |
Date: 2009-01-05 19:25 |
| You are right. (My dream is someday to completely get rid of this msvcrt stuff. Only pure Win32 API) |
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| msg79236 - (view) |
Author: Ulrich Eckhardt (eckhardt) |
Date: 2009-01-06 08:39 |
| I do have an issue with the patch's startup code. The prototype for the thread entry should be "DWORD WINAPI function(PVOID);". The important distinction is the WINAPI part, which resolves to __stdcall but doesn't have to. I know that some CE targets actually #define __cdecl __stdcall or vice versa, but using WINAPI always works. I'd then also change the comment to "...to adapt between our function signature and the one used by _createthreadex", as the internally used one doesn't mention __cdecl. |
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| msg79238 - (view) |
Author: Kristján Valur Jónsson (kristjan.jonsson) * |
Date: 2009-01-06 09:03 |
| No, the startup function for beginthreadex() must be __stdcall. From the docs: start_address Start address of a routine that begins execution of a new thread. For _beginthread, the calling convention is either __cdecl or __clrcall; for _beginthreadex, it is either __stdcall or __clrcall. (__clrcall is for managed code which doesn't apply). Do not confuse beginthreadex() with CreateThread even though they have similar arguments. The former is for use with programs using the crt. See http://msdn.microsoft.com/en-us/library/kdzttdcb.aspx for details. Amaury, Where did you find the value 1088 for maximum TLS slots? The documentation mentions the error condidion TLS_OUT_OF_INDEXES (which I should check for, I suppose), but nothing else. |
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| msg79239 - (view) |
Author: Ulrich Eckhardt (eckhardt) |
Date: 2009-01-06 09:08 |
| You're right, Kristján, sorry for the noise. Shouldn't make claims before being fully awake.... |
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| msg79499 - (view) |
Author: Kristján Valur Jónsson (kristjan.jonsson) * |
Date: 2009-01-09 20:04 |
| Committed this as revision: 68455 |
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| msg79503 - (view) |
Author: Martin v. Löwis (loewis) * |
Date: 2009-01-09 20:29 |
| Windows NT (3.1, and a number of later versions) only support 64 TLS keys. Starting with Windows 2000, they added another page per thread for TLS, giving an addition 1024 TLS slots, for a total of 1088 TLS slots. FWIW, Win 9.x supported 80 TLS slots. See http://www.nynaeve.net/?p=181 http://msdn.microsoft.com/en-us/library/ms686749.aspx http://bugs.python.org/file11141/thread_nt.patch TLS slots are typically considered a scarce resource, so that programming language implementations typically don't allow applications direct allocation of TLS slots. Instead, most runtimes I know of will allocate a single TLS slot for themselves, which then is filled with an array or a dictionary. |
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| msg79653 - (view) |
Author: Martin v. Löwis (loewis) * |
Date: 2009-01-12 08:25 |
| Please add a Misc/NEWS entry for this change. |
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| msg79656 - (view) |
Author: Kristján Valur Jónsson (kristjan.jonsson) * |
Date: 2009-01-12 09:19 |
| Note, see defect 4906 for fallout caused by this checkin. |
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| msg79657 - (view) |
Author: Kristján Valur Jónsson (kristjan.jonsson) * |
Date: 2009-01-12 09:21 |
| Misc/NEWS updated in revision: 68544 |
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| msg80154 - (view) |
Author: Kristján Valur Jónsson (kristjan.jonsson) * |
Date: 2009-01-19 10:31 |
| Note, this has been ported to py3k in http://svn.python.org/view? view=rev&rev=68543 |
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