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path: root/fs/bcachefs/mean_and_variance.h
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2024-07-19bcachefs: mean_and_variance: Avoid too-large shift amountsTavian Barnes1-3/+3
Shifting a value by the width of its type or more is undefined. Signed-off-by: Tavian Barnes <tavianator@tavianator.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-03-14bcachefs: mean_and_variance: put struct mean_and_variance_weighted on a dietDarrick J. Wong1-6/+8
The only caller of this code (time_stats) always knows the weights and whether or not any information has been collected. Pass this information into the mean and variance code so that it doesn't have to store that information. This reduces the structure size from 24 to 16 bytes, which shrinks each time_stats counter to 192 bytes from 208. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-29bcachefs: Fix build on parisc by avoiding __multi3()Helge Deller1-1/+1
The gcc compiler on paric does support the __int128 type, although the architecture does not have native 128-bit support. The effect is, that the bcachefs u128_square() function will pull in the libgcc __multi3() helper, which breaks the kernel build when bcachefs is built as module since this function isn't currently exported in arch/parisc/kernel/parisc_ksyms.c. The build failure can be seen in the latest debian kernel build at: https://buildd.debian.org/status/fetch.php?pkg=linux&arch=hppa&ver=6.7.1-1%7Eexp1&stamp=1706132569&raw=0 We prefer to not export that symbol, so fall back to the optional 64-bit implementation provided by bcachefs and thus avoid usage of __multi3(). Signed-off-by: Helge Deller <deller@gmx.de> Cc: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-01bcachefs: Fixes for rust bindgenKent Overstreet1-1/+4
bindgen doesn't seem to like u128 or DECLARE_FLEX_ARRAY(), but we can hack around them. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-23mean and variance: Add a missing includeKent Overstreet1-0/+1
abs() is in math.h Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-23mean and variance: More testsKent Overstreet1-8/+6
Add some more tests that test conventional and weighted mean simultaneously, and with a table of values that represents events that we'll be using this to look for so we can verify-by-eyeball that the output looks sane. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-23bcachefs: Mean and varianceDaniel Hill1-0/+199
This module provides a fast 64bit implementation of basic statistics functions, including mean, variance and standard deviation in both weighted and unweighted variants, the unweighted variant has a 32bit limitation per sample to prevent overflow when squaring. Signed-off-by: Daniel Hill <daniel@gluo.nz> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>