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Author	SHA1	Message	Date
Conrad Meyer	eefd8f96fb	geom_uzip(4), mkuzip(8): Add Zstd image mode The Zstd format bumps the CLOOP major number to 4 to avoid incompatibility with older systems. Support in geom_uzip(4) is conditional on the ZSTDIO kernel option, which is enabled in amd64 GENERIC, but not all in-tree configurations. mkuzip(8) was modified slightly to always initialize the nblocks + 1'th offset in the CLOOP file format. Previously, it was only initialized in the case where the final compressed block happened to be unaligned w.r.t. DEV_BSIZE. The "Fake" last+1 block change in r298619 means that the final compressed block's 'blen' was never correct unless the compressed uzip image happened to be BSIZE-aligned. This happened in about 1 out of every 512 cases. The zlib and lzma decompressors are probably tolerant of extra trash following the frame they were told to decode, but Zstd complains that the input size is incorrect. Correspondingly, geom_uzip(4) was modified slightly to avoid trashing the nblocks + 1'th offset when it is known to be initialized to a good value. This corrects the calculated final real cluster compressed length to match that printed by mkuzip(8). mkuzip(8) was refactored somewhat to reduce code duplication and increase ease of adding other compression formats. * Input block size validation was pulled out of individual compression init routines into main(). * Init routines now validate a user-provided compression level or select an algorithm-specific default, if none was provided. * A new interface for calculating the maximal compressed size of an incompressible input block was added for each driver. The generic code uses it to validate against MAXPHYS as well as to allocate compression result buffers in the generic code. * Algorithm selection is now driven by a table lookup, to increase ease of adding other formats in the future. mkuzip(8) gained the ability to explicitly specify a compression level with '-C'. The prior defaults -- 9 for zlib and 6 for lzma -- are maintained. The new zstd default is 9, to match zlib. Rather than select lzma or zlib with '-L' or its absense, respectively, a new argument '-A <algorithm>' is provided to select 'zlib', 'lzma', or 'zstd'. '-L' is considered deprecated, but will probably never be removed. All of the new features were documented in mkuzip.8; the page was also cleaned up slightly. Relnotes: yes	2019-08-13 23:32:56 +00:00
Maxim Sobolev	4fc55e3e46	Improve performance in a few key areas: o Split the compression across several worker threads. By default, "several" matches number of CPUs, capped at 24 for sanity when running on a very big hardwares. Provide option to set that number manually; o Fix bug inherited from the mkulzma (R.I.P) which degraded already slow LZMA compression even further by calling function to release compression state after processing each block. It is neither documented as required nor actually required by the LZMA library. This caused spree of system calls to release memory and then map it again for every block. LZMA compression is more than 2x faster after this change alone; o Record time it takes to do compression and report throughput achieved. o Add simple first-level 256 entry hash table for de-dup code, so it's not becoming a bottleneck at big files.	2016-04-23 07:23:43 +00:00
Maxim Sobolev	8f8cb840b0	Improve mkuzip(8) and geom_uzip(4), merge in LZMA support from mkulzma(8) and geom_uncompress(4): 1. mkuzip(8): - Proper support for eliminating all-zero blocks when compressing an image. This feature is already supported by the geom_uzip(4) module and CLOOP format in general, so it's just a matter of making mkuzip(8) match. It should be noted, however that this feature while it sounds great, results in very slight improvement in the overall compression ratio, since compressing default 16k all-zero block produces only 39 bytes compressed output block, which is 99.8% compression ratio. With typical average compression ratio of amd64 binaries and data being around 60-70% the difference between 99.8% and 100.0% is not that great further diluted by the ratio of number of zero blocks in the uncompressed image to the overall number of blocks being less than 0.5 (typically). However, this may be important from performance standpoint, so that kernel are not spinning its wheels decompressing those empty blocks every time this zero region is read. It could also be important when you create huge image mostly filled with zero blocks for testing purposes. - New feature allowing to de-duplicate output image. It turns out that if you twist CLOOP format a bit you can do that as well. And unlike zero-blocks elimination, this gives a noticeable improvement in the overall compression ratio, reducing output image by something like 3-4% on my test UFS2 3GB image consisting of full FreeBSD base system plus some of the packages (openjdk, apache etc), about 2.3GB worth of file data (800+MB compressed). The only caveat is that images created with this feature "on" would not work on older versions of FeeBSDxi kernel, hence it's turned off by default. - provide options to control both features and document them in manual page. - merge in all relevant LZMA compression support from the mkulzma(8), add new option to select between both. - switch license from ad-hoc beerware into standard 2-clause BSD. 2. geom_uzip(4): - implement support for de-duplicated images; - optimize some code paths to handle "all-zero" blocks without reading any compressed data; - beef up manual page to explain that geom_uzip(4) is not limited only to md(4) images. The compressed data can be written to the block device and accessed directly via magic of GEOM(4) and devfs(4), including to mount root fs from a compressed drive. - convert debug log code from being compiled in conditionally into being present all the time and provide two sysctls to turn it on or off. Due to intended use of the module, it can be used in environments where there may not be a luxury to put new kernel with debug code enabled. Having those options handy allows debug issues without as much problem by just having access to serial console or network shell access to a box/appliance. The resulting additional CPU cycles are just few int comparisons and branches, and those are minuscule when compared to data decompression which is the main feature of the module. - hopefully improve robustness and resiliency of the geom_uzip(4) by performing some of the data validation / range checking on the TOC entries and rejecting to attach to an image if those checks fail. - merge in all relevant LZMA decompression support from the geom_uncompress(4), enable automatically when appropriate format is indicated in the header. - move compilation work into its own worker thread so that it does not clog g_up. This allows multiple instances work in parallel utilizing smp cores. - document new knobs in the manual page. Reviewed by: adrian MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D5333	2016-02-23 23:59:08 +00:00

Author

SHA1

Message

Date

Conrad Meyer

eefd8f96fb

geom_uzip(4), mkuzip(8): Add Zstd image mode

The Zstd format bumps the CLOOP major number to 4 to avoid incompatibility
with older systems.  Support in geom_uzip(4) is conditional on the ZSTDIO
kernel option, which is enabled in amd64 GENERIC, but not all in-tree
configurations.

mkuzip(8) was modified slightly to always initialize the nblocks + 1'th
offset in the CLOOP file format.  Previously, it was only initialized in the
case where the final compressed block happened to be unaligned w.r.t.
DEV_BSIZE.  The "Fake" last+1 block change in r298619 means that the final
compressed block's 'blen' was never correct unless the compressed uzip image
happened to be BSIZE-aligned.  This happened in about 1 out of every 512
cases.  The zlib and lzma decompressors are probably tolerant of extra trash
following the frame they were told to decode, but Zstd complains that the
input size is incorrect.

Correspondingly, geom_uzip(4) was modified slightly to avoid trashing the
nblocks + 1'th offset when it is known to be initialized to a good value.
This corrects the calculated final real cluster compressed length to match
that printed by mkuzip(8).

mkuzip(8) was refactored somewhat to reduce code duplication and increase
ease of adding other compression formats.

  * Input block size validation was pulled out of individual compression
    init routines into main().

  * Init routines now validate a user-provided compression level or select
    an algorithm-specific default, if none was provided.

  * A new interface for calculating the maximal compressed size of an
    incompressible input block was added for each driver.  The generic code
    uses it to validate against MAXPHYS as well as to allocate compression
    result buffers in the generic code.

  * Algorithm selection is now driven by a table lookup, to increase ease of
    adding other formats in the future.

mkuzip(8) gained the ability to explicitly specify a compression level with
'-C'.  The prior defaults -- 9 for zlib and 6 for lzma -- are maintained.
The new zstd default is 9, to match zlib.

Rather than select lzma or zlib with '-L' or its absense, respectively, a
new argument '-A <algorithm>' is provided to select 'zlib', 'lzma', or
'zstd'.  '-L' is considered deprecated, but will probably never be removed.

All of the new features were documented in mkuzip.8; the page was also
cleaned up slightly.

Relnotes:	yes

2019-08-13 23:32:56 +00:00

Maxim Sobolev

4fc55e3e46

Improve performance in a few key areas:

o Split the compression across several worker threads. By default, "several"
   matches number of CPUs, capped at 24 for sanity when running on a very big
   hardwares. Provide option to set that number manually;

 o Fix bug inherited from the mkulzma (R.I.P) which degraded already slow LZMA
   compression even further by calling function to release compression state
   after processing each block.

   It is neither documented as required nor actually required by the LZMA
   library. This caused spree of system calls to release memory and then map
   it again for every block. LZMA compression is more than 2x faster after this
   change alone;

 o Record time it takes to do compression and report throughput achieved.

 o Add simple first-level 256 entry hash table for de-dup code, so it's not
   becoming a bottleneck at big files.

2016-04-23 07:23:43 +00:00

Maxim Sobolev

8f8cb840b0

Improve mkuzip(8) and geom_uzip(4), merge in LZMA support from mkulzma(8)

and geom_uncompress(4):

1. mkuzip(8):

 - Proper support for eliminating all-zero blocks when compressing an
   image. This feature is already supported by the geom_uzip(4) module
   and CLOOP format in general, so it's just a matter of making mkuzip(8)
   match. It should be noted, however that this feature while it sounds
   great, results in very slight improvement in the overall compression
   ratio, since compressing default 16k all-zero block produces only 39
   bytes compressed output block, which is 99.8% compression ratio. With
   typical average compression ratio of amd64 binaries and data being
   around 60-70% the difference between 99.8% and 100.0% is not that
   great further diluted by the ratio of number of zero blocks in the
   uncompressed image to the overall number of blocks being less than
   0.5 (typically). However, this may be important from performance
   standpoint, so that kernel are not spinning its wheels decompressing
   those empty blocks every time this zero region is read. It could also
   be important when you create huge image mostly filled with zero
   blocks for testing purposes.

 - New feature allowing to de-duplicate output image. It turns out that
   if you twist CLOOP format a bit you can do that as well. And unlike
   zero-blocks elimination, this gives a noticeable improvement in the
   overall compression ratio, reducing output image by something like
   3-4% on my test UFS2 3GB image consisting of full FreeBSD base system
   plus some of the packages (openjdk, apache etc), about 2.3GB worth of
   file data (800+MB compressed). The only caveat is that images created
   with this feature "on" would not work on older versions of FeeBSDxi
   kernel, hence it's turned off by default.

 - provide options to control both features and document them in manual
   page.

 - merge in all relevant LZMA compression support from the mkulzma(8),
   add new option to select between both.

 - switch license from ad-hoc beerware into standard 2-clause BSD.

2. geom_uzip(4):

 - implement support for de-duplicated images;

 - optimize some code paths to handle "all-zero" blocks without reading
   any compressed data;

 - beef up manual page to explain that geom_uzip(4) is not limited only
   to md(4) images. The compressed data can be written to the block
   device and accessed directly via magic of GEOM(4) and devfs(4),
   including to mount root fs from a compressed drive.

 - convert debug log code from being compiled in conditionally into
   being present all the time and provide two sysctls to turn it on or
   off. Due to intended use of the module, it can be used in
   environments where there may not be a luxury to put new kernel with
   debug code enabled. Having those options handy allows debug issues
   without as much problem by just having access to serial console or
   network shell access to a box/appliance. The resulting additional
   CPU cycles are just few int comparisons and branches, and those are
   minuscule when compared to data decompression which is the main
   feature of the module.

 - hopefully improve robustness and resiliency of the geom_uzip(4) by
   performing some of the data validation / range checking on the TOC
   entries and rejecting to attach to an image if those checks fail.

 - merge in all relevant LZMA decompression support from the
   geom_uncompress(4), enable automatically when appropriate format is
   indicated in the header.

 - move compilation work into its own worker thread so that it does not
   clog g_up. This allows multiple instances work in parallel utilizing
   smp cores.

 - document new knobs in the manual page.

Reviewed by:		adrian
MFC after:		1 month
Differential Revision:	https://reviews.freebsd.org/D5333

2016-02-23 23:59:08 +00:00

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