* [GIT PULL] zstd fixes for v5.16-rc1
@ 2021-11-18 21:22 Nick Terrell
2021-11-19 1:13 ` pr-tracker-bot
0 siblings, 1 reply; 2+ messages in thread
From: Nick Terrell @ 2021-11-18 21:22 UTC (permalink / raw)
To: Linus Torvalds
Cc: Linux Kernel Mailing List, Parisc List, Kernel Team,
Geert Uytterhoeven, Helge Deller
Hi Linus,
The following changes since commit fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf:
Linux 5.16-rc1 (2021-11-14 13:56:52 -0800)
are available in the Git repository at:
git://github.com/terrelln/linux.git tags/zstd-for-linus-5.16-rc1
for you to fetch changes up to 7416cdc9b9c10968c57b1f73be5d48b3ecdaf3c8:
lib: zstd: Don't add -O3 to cflags (2021-11-18 13:16:22 -0800)
Best,
Nick Terrell
----------------------------------------------------------------
zstd fixes for v5.16-rc1
Fix stack usage on parisc & improve code size bloat
This PR contains 3 commits:
1. Fixes a minor unused variable warning reported by Kernel test robot [0].
2. Improves the reported code bloat (-88KB / 374KB) [1] by outlining
some functions that are unlikely to be used in performance sensitive
workloads.
3. Fixes the reported excess stack usage on parisc [2] by removing -O3
from zstd's compilation flags. -O3 triggered bugs in the hppa-linux-gnu
gcc-8 compiler. -O2 performance is acceptable: neutral compression,
about -1% decompression speed. We also reduce code bloat
(-105KB / 374KB).
After this commit our code bloat is cut from 374KB to 105KB with gcc-11.
If we wanted to cut the remaining 105KB we'd likely have to trade
signicant performance, so I want to say that this is enough for now.
We should be able to get further gains without sacrificing speed, but
that will take some significant optimization effort, and isn't suitable
for a quick fix. I've opened an upstream issue [3] to track the code size,
and try to avoid future regressions, and improve it in the long term.
[0] https://lore.kernel.org/linux-mm/202111120312.833wII4i-lkp@intel.com/T/
[1] https://lkml.org/lkml/2021/11/15/710
[2] https://lkml.org/lkml/2021/11/14/189
[3] https://github.com/facebook/zstd/issues/2867
Link: https://lore.kernel.org/r/20211117014949.1169186-1-nickrterrell@gmail.com/
Link: https://lore.kernel.org/r/20211117201459.1194876-1-nickrterrell@gmail.com/
Signed-off-by: Nick Terrell <terrelln@fb.com>
----------------------------------------------------------------
Nick Terrell (3):
lib: zstd: Fix unused variable warning
lib: zstd: Don't inline functions in zstd_opt.c
lib: zstd: Don't add -O3 to cflags
lib/zstd/Makefile | 2 --
lib/zstd/common/compiler.h | 7 +++++++
lib/zstd/compress/zstd_compress_superblock.c | 2 ++
lib/zstd/compress/zstd_opt.c | 12 ++++++++++++
4 files changed, 21 insertions(+), 2 deletions(-)
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* Re: [GIT PULL] zstd fixes for v5.16-rc1
2021-11-18 21:22 [GIT PULL] zstd fixes for v5.16-rc1 Nick Terrell
@ 2021-11-19 1:13 ` pr-tracker-bot
0 siblings, 0 replies; 2+ messages in thread
From: pr-tracker-bot @ 2021-11-19 1:13 UTC (permalink / raw)
To: Nick Terrell
Cc: Linus Torvalds, Linux Kernel Mailing List, Parisc List,
Kernel Team, Geert Uytterhoeven, Helge Deller
The pull request you sent on Thu, 18 Nov 2021 21:22:35 +0000:
> git://github.com/terrelln/linux.git tags/zstd-for-linus-5.16-rc1
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/4c388a8e740d3235a194f330c8ef327deef710f6
Thank you!
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