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This version is outdated by a newer approved version.DiffThis version (20 Aug 2021 10:03) is a draft.
Approvals: 0/1

This is an old revision of the document!

Table of Contents

IIO System Considerations Tips & Tricks

IIO context timeout (libiio)

  • May be triggered by low sample rates and large buffers
  • Long blocking calls (some calibration, profile load, etc.)
Increase iio_context_set_timeout() timeout parameter or set to 0 to disables the timeout

Buffer handling, sizes and counts

Typically set to a frame or chunk size suitable for signal processing (e.g. N x FFT_size)

  • Small buffers → less latency but more overhead
  • Large buffers → less overhead but more latency
Number of discrete buffers are configurable, default is 4.
Can change this using iio_device_set_kernel_buffers_count()
Capturing starts as soon as the buffer is created!
iio_device_create_buffer()
FIFO like behavior new data is dropped in case it's not consumed fast enough!

IIO buffer DMA max block size

Max buffer size is limited by the max_block_size parameter

  • Default 16M
  • Can be adjusted

There are two ways to adjust the max block size

sysfs

Set via /sys/module/industrialio_buffer_dma/parameters/max_block_size in bytes

This specifies any shell prompt running on the target 

root@analog:~# echo 67108864 > /sys/module/industrialio_buffer_dma/parameters/max_block_size
root@analog:~# cat /sys/module/industrialio_buffer_dma/parameters/max_block_size
67108864
root@analog:~#

Kernel command line

Append the following to your kernel command line

  • industrialio_buffer_dma.max_block_size=size_in_bytes
resources/tools-software/linux-software/libiio_tips_tricks.1629446625.txt.gz · Last modified: 20 Aug 2021 10:03 by Michael Hennerich

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