[media][dvb-core] Question on dvr device copy

[media][dvb-core] Question on dvr device copy

[Hamad Kadmany]

Hi,

Currently when playing stream from memory through dvr device (through write
calls), the written buffer is copied from user-space to kernel space. The
same applies when recording a stream, the TS packets received from HW are
copied to dvr ring-buffer.

I'm a bit concerned about the performance due to the copy, and whether we
better have a memory mapped ring-buffer in dvr device output and/or dvr
device input with user-space to cope with high bitrate streams.

Your feedback on this will be mostly appreciated.

Thanks
Hamad

RE: [media][dvb-core] Question on dvr device copy

[Hamad Kadmany]

Hi,

I would appreciate if anyone can feedback on this, I'm considering
implementing mmap in demux/dvr devices so that user-space can access the
input/output buffers directly without the need for read/write operations.

Thanks
Hamad

-----Original Message-----
From: linux-media-owner@vger.kernel.org
[mailto:linux-media-owner@vger.kernel.org] On Behalf Of Hamad Kadmany
Sent: Sunday, February 12, 2012 4:19 PM
To: linux-media@vger.kernel.org
Subject: [media][dvb-core] Question on dvr device copy 

Hi,

Currently when playing stream from memory through dvr device (through write
calls), the written buffer is copied from user-space to kernel space. The
same applies when recording a stream, the TS packets received from HW are
copied to dvr ring-buffer.

I'm a bit concerned about the performance due to the copy, and whether we
better have a memory mapped ring-buffer in dvr device output and/or dvr
device input with user-space to cope with high bitrate streams.

Your feedback on this will be mostly appreciated.

Thanks
Hamad

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