diff options
| author | Phillip Lougher <phillip@squashfs.org.uk> | 2013-11-18 02:31:36 +0000 |
|---|---|---|
| committer | Phillip Lougher <phillip@squashfs.org.uk> | 2013-11-20 03:58:03 +0000 |
| commit | d208383d640727b70cd6689bc17e67e9b5ebf4ff (patch) | |
| tree | 03a6146c22473beb13e2ebda605d6a332ddb758b /fs/squashfs/Kconfig | |
| parent | cd59c2ec5f37a2bc1315c9324aab6c21d43ffa1a (diff) | |
Squashfs: add multi-threaded decompression using percpu variable
Add a multi-threaded decompression implementation which uses
percpu variables.
Using percpu variables has advantages and disadvantages over
implementations which do not use percpu variables.
Advantages:
* the nature of percpu variables ensures decompression is
load-balanced across the multiple cores.
* simplicity.
Disadvantages: it limits decompression to one thread per core.
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Diffstat (limited to 'fs/squashfs/Kconfig')
| -rw-r--r-- | fs/squashfs/Kconfig | 57 |
1 files changed, 44 insertions, 13 deletions
diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig index 1c6d340fc61f..159bd6676dc2 100644 --- a/fs/squashfs/Kconfig +++ b/fs/squashfs/Kconfig @@ -25,6 +25,50 @@ config SQUASHFS If unsure, say N. +choice + prompt "Decompressor parallelisation options" + depends on SQUASHFS + help + Squashfs now supports three parallelisation options for + decompression. Each one exhibits various trade-offs between + decompression performance and CPU and memory usage. + + If in doubt, select "Single threaded compression" + +config SQUASHFS_DECOMP_SINGLE + bool "Single threaded compression" + help + Traditionally Squashfs has used single-threaded decompression. + Only one block (data or metadata) can be decompressed at any + one time. This limits CPU and memory usage to a minimum. + +config SQUASHFS_DECOMP_MULTI + bool "Use multiple decompressors for parallel I/O" + help + By default Squashfs uses a single decompressor but it gives + poor performance on parallel I/O workloads when using multiple CPU + machines due to waiting on decompressor availability. + + If you have a parallel I/O workload and your system has enough memory, + using this option may improve overall I/O performance. + + This decompressor implementation uses up to two parallel + decompressors per core. It dynamically allocates decompressors + on a demand basis. + +config SQUASHFS_DECOMP_MULTI_PERCPU + bool "Use percpu multiple decompressors for parallel I/O" + help + By default Squashfs uses a single decompressor but it gives + poor performance on parallel I/O workloads when using multiple CPU + machines due to waiting on decompressor availability. + + This decompressor implementation uses a maximum of one + decompressor per core. It uses percpu variables to ensure + decompression is load-balanced across the cores. + +endchoice + config SQUASHFS_XATTR bool "Squashfs XATTR support" depends on SQUASHFS @@ -63,19 +107,6 @@ config SQUASHFS_LZO If unsure, say N. -config SQUASHFS_MULTI_DECOMPRESSOR - bool "Use multiple decompressors for handling parallel I/O" - depends on SQUASHFS - help - By default Squashfs uses a single decompressor but it gives - poor performance on parallel I/O workloads when using multiple CPU - machines due to waiting on decompressor availability. - - If you have a parallel I/O workload and your system has enough memory, - using this option may improve overall I/O performance. - - If unsure, say N. - config SQUASHFS_XZ bool "Include support for XZ compressed file systems" depends on SQUASHFS |