On 12/12/2023 6:14 PM, Rafael J. Wysocki wrote:
Hi,
On Wed, Nov 29, 2023 at 11:20 AM Nikhil V <quic_nprakash@xxxxxxxxxxx> wrote:
On 11/15/2023 5:52 PM, Nikhil V wrote:
This patch series covers the following:
1. Renaming lzo* to generic names, except for lzo_xxx() APIs. This is
used in the next patch where we move to crypto based APIs for
compression. There are no functional changes introduced by this
approach.
2. Replace LZO library calls with crypto generic APIs
Currently for hibernation, LZO is the only compression algorithm
available and uses the existing LZO library calls. However, there
is no flexibility to switch to other algorithms which provides better
results. The main idea is that different compression algorithms have
different characteristics and hibernation may benefit when it uses
alternate algorithms.
By moving to crypto based APIs, it lays a foundation to use other
compression algorithms for hibernation.
3. LZ4 compression
Extend the support for LZ4 compression to be used with hibernation.
The main idea is that different compression algorithms have different
characteristics and hibernation may benefit when it uses any of these
algorithms: a default algorithm, having higher compression rate but is
slower(compression/decompression) and a secondary algorithm, that is
faster(compression/decompression) but has lower compression rate.
LZ4 algorithm has better decompression speeds over LZO. This reduces
the hibernation image restore time.
As per test results:
LZO LZ4
Size before Compression(bytes) 682696704 682393600
Size after Compression(bytes) 146502402 155993547
Decompression Rate 335.02 MB/s 501.05 MB/s
Restore time 4.4s 3.8s
LZO is the default compression algorithm used for hibernation. Enable
CONFIG_HIBERNATION_DEF_COMP_LZ4 to set the default compressor as LZ4.
Compression Benchmarks: https://github.com/lz4/lz4
4. Support to select compression algorithm
Currently the default compression algorithm is selected based on
Kconfig. Introduce a kernel command line parameter "hib_compression" to
override this behaviour.
Users can set "hib_compression" command line parameter to specify
the algorithm.
Usage:
LZO: hib_compression=lzo
LZ4: hib_compression=lz4
LZO is the default compression algorithm used with hibernation.
Changes in v2:
- Fixed build issues reported by kernel test robot for ARCH=sh, [1].
[1] https://lore.kernel.org/oe-kbuild-all/202310171226.pLUPeuC7-lkp@xxxxxxxxx/
Nikhil V (4):
PM: hibernate: Rename lzo* to make it generic
PM: hibernate: Move to crypto APIs for LZO compression
PM: hibernate: Add support for LZ4 compression for hibernation
PM: hibernate: Support to select compression algorithm
.../admin-guide/kernel-parameters.txt | 6 +
kernel/power/Kconfig | 26 ++-
kernel/power/hibernate.c | 85 +++++++-
kernel/power/power.h | 19 ++
kernel/power/swap.c | 189 +++++++++++-------
5 files changed, 251 insertions(+), 74 deletions(-)
base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86
Hi @Rafael/@Pavel/@Len,
Could you please let me know if you have any concerns on this approach?
Not really a concern, but that is a significant change that I would
rather make early in the cycle, which means after the 6.8 merge
window.
No need to resend unless there is something to address in which case
I'll let you know.
Thanks!
FYI: We have tested this on QEMU and its working fine.
Logs(suspend):
[ 75.242227] PM: Using 3 thread(s) for lz4 compression
[ 75.243043] PM: Compressing and saving image data (17495 pages)...
[ 75.243917] PM: Image saving progress: 0%
[ 75.261727] PM: Image saving progress: 10%
[ 75.277968] PM: Image saving progress: 20%
[ 75.290927] PM: Image saving progress: 30%
[ 75.305186] PM: Image saving progress: 40%
[ 75.318252] PM: Image saving progress: 50%
[ 75.330310] PM: Image saving progress: 60%
[ 75.345906] PM: Image saving progress: 70%
[ 75.359054] PM: Image saving progress: 80%
[ 75.372176] PM: Image saving progress: 90%
[ 75.388411] PM: Image saving progress: 100%
[ 75.389775] PM: Image saving done
[ 75.390397] PM: hibernation: Wrote 69980 kbytes in 0.14 seconds
(499.85 MB/s)
[ 75.391591] PM: Image size after compression: 28242 kbytes
[ 75.393089] PM: S|
[ 75.399784] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[ 75.439170] sd 0:0:0:0: [sda] Stopping disk
[ 75.501461] ACPI: PM: Preparing to enter system sleep state S5
[ 75.502766] reboot: Power down
Logs(resume):
[ 1.063248] PM: hibernation: resume from hibernation
[ 1.072868] Freezing user space processes
[ 1.073707] Freezing user space processes completed (elapsed 0.000
seconds)
[ 1.075192] OOM killer disabled.
[ 1.075837] Freezing remaining freezable tasks
[ 1.078010] Freezing remaining freezable tasks completed (elapsed
0.001 seconds)
[ 1.087489] PM: Using 3 thread(s) for lz4 decompression
[ 1.088570] PM: Loading and decompressing image data (17495 pages)...
[ 1.125549] PM: Image loading progress: 0%
[ 1.190380] PM: Image loading progress: 10%
[ 1.204963] PM: Image loading progress: 20%
[ 1.218988] PM: Image loading progress: 30%
[ 1.233697] PM: Image loading progress: 40%
[ 1.248658] PM: Image loading progress: 50%
[ 1.262910] PM: Image loading progress: 60%
[ 1.276966] PM: Image loading progress: 70%
[ 1.290517] PM: Image loading progress: 80%
[ 1.305427] PM: Image loading progress: 90%
[ 1.320666] PM: Image loading progress: 100%
[ 1.321866] PM: Image loading done
[ 1.322599] PM: hibernation: Read 69980 kbytes in 0.23 seconds
(304.26 MB/s)
[ 1.324795] printk: Suspending console(s) (use no_console_suspend to
debug)
[ 74.943801] ata1.00: Entering standby power mode
Thanks,
Nikhil V
Hi @Rafael
We have picked this patch series on 6.8-rc1 and tested the functionality
on QEMU. Its working fine. However, while applying the patches we could
see minor conflicts. Could you please let me know if we need to push a
new version after resolving these conflicts?
Thanks,
Nikhil V
