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Windows: Max 256 concurrent transfers supported on Windows #92

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mcuee opened this issue Aug 17, 2015 · 3 comments
Closed

Windows: Max 256 concurrent transfers supported on Windows #92

mcuee opened this issue Aug 17, 2015 · 3 comments
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enhancement New features windows
Milestone
2.0 release (API/...

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@mcuee
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mcuee commented Aug 17, 2015

Ref:
http://libusb.org/ticket/157
http://comments.gmane.org/gmane.comp.lib.libusbx.devel/1881

A fixed size array of per-transfer data structures internal to the Windows backend limits the number of concurrent transfers.
@mcuee mcuee added the enhancement New features label Aug 17, 2015
@mcuee mcuee added this to the V2.0 release (API/ABI change) milestone Aug 17, 2015
@hiyuh
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hiyuh commented Nov 20, 2015

maybe due to compiler optimization applied,
i may have max 128 fds limit as variant of this issue on cygwin.
also using int to index poll_fd[] looks simply uncool.

@dickens
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dickens commented Dec 2, 2015

The maximum number of 256 transfers will be lifted when the event
abstraction code is merged in, but there will still remain a limit of 64
(MAXIMUM_WAIT_OBJECTS) per context. (Actually, there will be 62 transfers
available, since 2 HANDLEs will be reserved for the context event and
timer). The limit can be lifted altogether if the Windows backend uses the
RegisterWaitForSingleObject() API, but there is a measurable performance
penalty in doing so.

On Thu, Nov 19, 2015 at 6:26 PM, KIMURA Masaru notifications@github.com
wrote:

maybe due to compiler optimization applied,
i may have max 128 fds limit as variant of this issue on cygwin.
also using int to index poll_fd[] looks simply uncool.

—
Reply to this email directly or view it on GitHub
#92 (comment).

@hjelmn hjelmn added the windows label Mar 5, 2016
@dickens
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dickens commented Jan 14, 2020

Closing as this was addressed in #592.

@dickens dickens closed this as completed Jan 14, 2020
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