linux-toradex.git/Documentation/ABI/testing/sysfs-block, branch Rel3

block: Add sysfs documentation for the discard topology parameters

2011-05-18T08:37:39+00:00

Add documentation for the discard I/O topology parameters exported in
sysfs.

Signed-off-by: Martin K. Petersen 
Signed-off-by: Jens Axboe

block: Added in stricter no merge semantics for block I/O

2010-01-29T08:04:08+00:00

Updated 'nomerges' tunable to accept a value of '2' - indicating that _no_
merges at all are to be attempted (not even the simple one-hit cache).

The following table illustrates the additional benefit - 5 minute runs of
a random I/O load were applied to a dozen devices on a 16-way x86_64 system.

nomerges        Throughput      %System         Improvement (tput / %sys)
--------        ------------    -----------     -------------------------
0               12.45 MB/sec    0.669365609
1               12.50 MB/sec    0.641519199     0.40% / 2.71%
2               12.52 MB/sec    0.639849750     0.56% / 2.96%

Signed-off-by: Alan D. Brunelle 
Signed-off-by: Jens Axboe

tree-wide: fix assorted typos all over the place

2009-12-04T14:39:55+00:00

That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.

Signed-off-by: André Goddard Rosa 
Signed-off-by: Jiri Kosina

block: Update topology documentation

2009-08-01T08:24:35+00:00

Update topology comments and sysfs documentation based upon discussions
with Neil Brown.

Signed-off-by: Martin K. Petersen 
Signed-off-by: Jens Axboe

block: Export I/O topology for block devices and partitions

2009-05-22T21:22:55+00:00

To support devices with physical block sizes bigger than 512 bytes we
need to ensure proper alignment.  This patch adds support for exposing
I/O topology characteristics as devices are stacked.

  logical_block_size is the smallest unit the device can address.

  physical_block_size indicates the smallest I/O the device can write
  without incurring a read-modify-write penalty.

  The io_min parameter is the smallest preferred I/O size reported by
  the device.  In many cases this is the same as the physical block
  size.  However, the io_min parameter can be scaled up when stacking
  (RAID5 chunk size > physical block size).

  The io_opt characteristic indicates the optimal I/O size reported by
  the device.  This is usually the stripe width for arrays.

  The alignment_offset parameter indicates the number of bytes the start
  of the device/partition is offset from the device's natural alignment.
  Partition tools and MD/DM utilities can use this to pad their offsets
  so filesystems start on proper boundaries.

Signed-off-by: Martin K. Petersen 
Signed-off-by: Jens Axboe

block: Data integrity infrastructure documentation

2008-07-03T11:21:13+00:00

Signed-off-by: Martin K. Petersen 
Signed-off-by: Jens Axboe

Enhanced partition statistics: documentation update

2008-02-08T11:42:11+00:00

Update the documentation to reflect the change in userspace interface.

Signed-off-by: Jerome Marchand 
Signed-off-by: Jens Axboe