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Pipe limit?

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Holger Kleinsorgen

Pipe limit?

Hi,

is there some kind of limit regarding the number of concurrent pipes to external processes on Windows?
I'm spawning 16 processes and want to redirect the output to Stdout, but I get the following exception.
It doesnt crash when I spawn 8 processes.

Cause of Dump: Unhandled exception: out of threads

Context Stack:
[1] Win32SystemSupport(ExternalInterface)>>externalAccessFailedWith:
[2] Win32SystemSupport>>externalAccessFailedWith:
[3] Win32SystemSupport>>WriteFile:lpBuffer:nNumberOfBytesToWrite:lpNumberOfBytesWritten:lpOverlapped:
[4] Win32SystemSupport>>okWriteFile:lpBuffer:nNumberOfBytesToWrite:lpNumberOfBytesWritten:lpOverlapped:
[5] optimized [] in PCPipeAccessor>>primWriteFrom:startingAt:for:
[6] BlockClosure>>ensure:
[7] PCPipeAccessor>>primWriteFrom:startingAt:for:
[8] PCPipeAccessor(IOAccessor)>>writeFrom:startingAt:forSure:
[9] IOBuffer>>flushBufferUpTo:
[10] ExternalWriteStream>>flush
[11] optimized [] in StandardIOStream>>nextPut:

Holger Kleinsorgen

Re: Pipe limit?

Forgot: this is 7.7 on Windows 7

Steven Kelly

Re: Pipe limit?

In reply to this post by Holger Kleinsorgen

[vwnc] Pipe limit?

See DLLandCConnectGuide 5-15 Thread Limit and Low Tide:

"THAPI provides a hard limit on the maximum number of threads that can be created and a low-tide limit on the number of quiescent threads. When the Object Engine starts up, it initializes both the upper and lower thread limits to 32."

The subsequent paragraphs have the details and show what can be changed and how.

Steve

From: [hidden email] on behalf of Holger Kleinsorgen
Sent: Wed 24/06/2015 20:54
To: [hidden email]
Subject: [vwnc] Pipe limit?

Hi,

is there some kind of limit regarding the number of concurrent pipes to
external processes on Windows?
I'm spawning 16 processes and want to redirect the output to Stdout, but I
get the following exception.
It doesnt crash when I spawn 8 processes.

Cause of Dump: Unhandled exception: out of threads

Context Stack:
[1]     Win32SystemSupport(ExternalInterface)>>externalAccessFailedWith:
[2]     Win32SystemSupport>>externalAccessFailedWith:
[3]
Win32SystemSupport>>WriteFile:lpBuffer:nNumberOfBytesToWrite:lpNumberOfBytesWritten:lpOverlapped:
[4]
Win32SystemSupport>>okWriteFile:lpBuffer:nNumberOfBytesToWrite:lpNumberOfBytesWritten:lpOverlapped:
[5]     optimized [] in PCPipeAccessor>>primWriteFrom:startingAt:for:
[6]     BlockClosure>>ensure:
[7]     PCPipeAccessor>>primWriteFrom:startingAt:for:
[8]     PCPipeAccessor(IOAccessor)>>writeFrom:startingAt:forSure:
[9]     IOBuffer>>flushBufferUpTo:
[10]    ExternalWriteStream>>flush
[11]    optimized [] in StandardIOStream>>nextPut:

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Holger Kleinsorgen

Re: Pipe limit?

Thanks, Steve, that solved my problem. Each forked process has two pipes (stdout + sterr), so I hit the 32 threads limit.

Steven Kelly wrote

See DLLandCConnectGuide 5-15 Thread Limit and Low Tide:
"THAPI provides a hard limit on the maximum number of threads that can be
created and a low-tide limit on the number of quiescent threads. When the
Object Engine starts up, it initializes both the upper and lower thread
limits to 32."

The subsequent paragraphs have the details and show what can be changed and
how.