24 Mar, 2012
40 commits
-
Add two changes that improve the performance of x86 systems
1. replace main loop with incrementing counter this change improves
the performance of the selftest by about 5-6% on Nehalem CPUs. The
apparent reason is that the compiler can use the loop index to perform
an indexed memory access. This is reported to make the performance of
PowerPC CPUs to get worse.2. replace the rem_len loop with incrementing counter this change
improves the performance of the selftest, which has more than the usual
number of occurances, by about 1-2% on x86 CPUs. In actual work loads
the length is most often a multiple of 4 bytes and this code does not
get executed as often if at all. Again this change is reported to make
the performance of PowerPC get worse.[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson
Signed-off-by: Darrick J. Wong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add slicing-by-8 algorithm to the existing slicing-by-4 algorithm. This
consists of:- extend largest BITS size from 32 to 64
- extend tables from tab[4][256] to up to tab[8][256]
- Add code for inner loop.[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson
Signed-off-by: Darrick J. Wong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
crc32.c provides a choice of one of several algorithms for computing the
LSB and LSB versions of the CRC32 checksum based on the parameters
CRC_LE_BITS and CRC_BE_BITS.In the original version the values 1, 2, 4 and 8 respectively selected
versions of the alrogithm that computed the crc 1, 2, 4 and 32 bits as a
time.This patch series adds a new version that computes the CRC 64 bits at a
time. To make things easier to understand the parameter has been
reinterpreted to actually stand for the number of bits processed in each
step of the algorithm so that the old value 8 has been replaced with the
value 32.This also allows us to add in a widely used crc algorithm that computes
the crc 8 bits at a time called the Sarwate algorithm.[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson
Signed-off-by: Darrick J. Wong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
crc32.c in its original version freely mixed u32, __le32 and __be32 types
which caused warnings from sparse with __CHECK_ENDIAN__. This patch fixes
these by forcing the types to u32.[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson
Signed-off-by: Darrick J. Wong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Misc cleanup of lib/crc32.c and related files.
- remove unnecessary header files.
- straighten out some convoluted ifdef's
- rewrite some references to 2 dimensional arrays as 1 dimensional
arrays to make them correct. I.e. replace tab[i] with tab[0][i].- a few trivial whitespace changes
- fix a warning in gen_crc32tables.c caused by a mismatch in the type of
the pointer passed to output table. Since the table is only used at
kernel compile time, it is simpler to make the table big enough to hold
the largest column size used. One cannot make the column size smaller
in output_table because it has to be used by both the le and be tables
and they can have different column sizes.[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson
Signed-off-by: Darrick J. Wong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Replace the unit test provided in crc32.c, which doesn't have a makefile
and doesn't compile with current headers, with a simpler self test
routine that also gives a measure of performance and runs at module init
time. The self test option can be enabled through a configuration
option CONFIG_CRC32_SELFTEST.The test stresses the pre and post loops and is thus not very realistic
since actual uses will likely have addresses and lengths that are at
least 4 byte aligned. However, the main loop is long enough so that the
performance is dominated by that loop.The expected values for crc32_le and crc32_be were generated with the
original version of crc32.c using CRC_BITS_LE = 8 and CRC_BITS_BE = 8.
These values were then used to check all the values of the BITS
parameters in both the original and new versions.The performance results show some variability from run to run in spite
of attempts to both warm the cache and reduce the amount of OS noise by
limiting interrutps during the test. To get comparable results and to
analyse options wrt performance the best time reported over a small
sample of runs has been taken.[djwong@us.ibm.com: Minor changelog tweaks]
Signed-off-by: Bob Pearson
Signed-off-by: Darrick J. Wong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move a long comment from lib/crc32.c to Documentation/crc32.txt where it
will more likely get read.Edited the resulting document to add an explanation of the slicing-by-n
algorithm.[djwong@us.ibm.com: minor changelog tweaks]
[akpm@linux-foundation.org: fix typo, per George]
Signed-off-by: George Spelvin
Signed-off-by: Bob Pearson
Signed-off-by: Darrick J. Wong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patchset (re)uses Bob Pearson's crc32 slice-by-8 code to stamp out
a software crc32c implementation. It removes the crc32c implementation
in crypto/ in favor of using the stamped-out one in lib/. There is also
a change to Kconfig so that the kernel builder can pick an
implementation best suited for the hardware.The motivation for this patchset is that I am working on adding full
metadata checksumming to ext4. As far as performance impact of adding
checksumming goes, I see nearly no change with a standard mail server
ffsb simulation. On a test that involves only file creation and
deletion and extent tree writes, I see a drop of about 50 pcercent with
the current kernel crc32c implementation; this improves to a drop of
about 20 percent with the enclosed crc32c code.When metadata is usually a small fraction of total IO, this new
implementation doesn't help much because metadata is usually a small
fraction of total IO. However, when we are doing IO that is almost all
metadata (such as rm -rf'ing a tree), then this patch speeds up the
operation substantially.Incidentally, given that iscsi, sctp, and btrfs also use crc32c, this
patchset should improve their speed as well. I have not yet quantified
that, however. This latest submission combines Bob's patches from late
August 2011 with mine so that they can be one coherent patch set.
Please excuse my inability to combine some of the patches; I've been
advised to leave Bob's patches alone and build atop them instead. :/Since the last posting, I've also collected some crc32c test results on
a bunch of different x86/powerpc/sparc platforms. The results can be
viewed here: http://goo.gl/sgt3i ; the "crc32-kern-le" and "crc32c"
columns describe the performance of the kernel's current crc32 and
crc32c software implementations. The "crc32c-by8-le" column shows
crc32c performance with this patchset applied. I expect crc32
performance to be roughly the same.The two _boost columns at the right side of the spreadsheet shows how much
faster the new implementation is over the old one. As you can see, crc32
rises substantially, and crc32c experiences a huge increase.This patch:
- remove trailing whitespace from lib/crc32.c
- remove trailing whitespace from lib/crc32defs.h[djwong@us.ibm.com: changelog tweaks]
Signed-off-by: Bob Pearson
Signed-off-by: Darrick J. Wong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
checkpatch already makes an exception to the 80-column rule for quoted
strings, and Documentation/CodingStyle recommends not splitting quoted
strings across lines, because it breaks the ability to grep for the
string. Rather than just permitting this, actively warn about quoted
strings split across lines.Test case:
void context(void)
{
struct { unsigned magic; const char *strdata; } foo[] = {
{ 42, "these strings"
"do not produce warnings" },
{ 256, "though perhaps"
"they should" },
};
pr_err("this string"
" should produce a warning\n");
pr_err("this multi-line string\n"
"should not produce a warning\n");
asm ("this asm\n\t"
"should not produce a warning");
}Results of checkpatch on that test case:
WARNING: quoted string split across lines
+ " should produce a warning\n");total: 0 errors, 1 warnings, 15 lines checked
Signed-off-by: Josh Triplett
Acked-by: Joe Perches
Cc: Andy Whitcroft
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add blank lines between a few tests, remove an extraneous one.
Signed-off-by: Joe Perches
Cc: Andy Whitcroft
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Using yield() is generally wrong. Warn on its use.
Signed-off-by: Joe Perches
Cc: Andy Whitcroft
Cc: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add some more subjective --strict tests.
Add a test for block comments that start with a blank line followed only
by a line with just the comment block initiator. Prefer a blank line
followed by /* comment...Add a test for unnecessary spaces after a cast.
Add a test for symmetric uses of braces in if/else blocks.
If one branch needs braces, then all branches should use braces.Signed-off-by: Joe Perches
Cc: Andy Whitcroft
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add [] to a type extensions. Fixes false positives on:
.attrs = (struct attribute *[]) {
Signed-off-by: Andy Whitcroft
Cc: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
With any very high precedence operator it is not necessary to enforce
additional parentheses around simple negated expressions. This prevents
us requesting further perentheses around the following:#define PMEM_IS_FREE(id, index) !(pmem[id].bitmap[index].allocated)
For now add logical and bitwise not and unary minus.
Signed-off-by: Andy Whitcroft
Cc: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Adjacent strings indicate concatentation, therefore look at identifiers
directly adjacent to literal strings as strings too. This allows us to
better detect the form below and accept it as a simple constant:#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
Signed-off-by: Andy Whitcroft
Cc: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Signed-off-by: Andy Whitcroft
Cc: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Handle the [ A ... B ] form deeper into a definition, for example:
static const unsigned char pci_irq_swizzle[2][PCI_MAX_DEVICES] = {
{0, 0, 0, 0, 0, 0, 0, 27, 27, [9 ... PCI_MAX_DEVICES - 1] = 0 },
{0, 0, 0, 0, 0, 0, 0, 29, 29, [9 ... PCI_MAX_DEVICES - 1] = 0 },
};Reported-by: Marek Vasut
Signed-off-by: Andy Whitcroft
Cc: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Fix checkpatch.pl when both -q and --ignore are given and prevents it from
printing aNOTE: Ignored message types: blah
messages.
E.g., if I use -q --ignore PREFER_PACKED,PREFER_ALIGNED, i see:
NOTE: Ignored message types: PREFER_ALIGNED PREFER_PACKED
It makes no sense to print this when -q is given.
Signed-off-by: Artem Bityutskiy
Cc: Andy Whitcroft
Cc: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Argument alignment across multiple lines should match the open
parenthesis.Logical continuations should be at the end of the previous line, not the
start of a new line.These are not required by CodingStyle so make the tests active only when
using --strict.Improved by some examples from Bruce Allen.
Signed-off-by: Joe Perches
Cc: "Bruce W. Allen"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
It's equivalent to __printf, so prefer __scanf.
Signed-off-by: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Introduce prio_set_parent() to abstract the operation which is used to
attach the node to its parent.Signed-off-by: Xiao Guangrong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
In current code, the deleted-node is recorded from first to last,
actually, we can directly attach these node on 'node' we will insert as
the left child, it can let the code more readable.Signed-off-by: Xiao Guangrong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Introduce iter_walk_down()/iter_walk_up() to remove the common code
between prio_tree_left() and prio_tree_right().Signed-off-by: Xiao Guangrong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remove the code since 'node' has already been initialized in the begin of
the functionSigned-off-by: Xiao Guangrong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
- Generate a 64-bit pattern more efficiently
memchr_inv needs to generate a 64-bit pattern filled with a target
character. The operation can be done by more efficient way.- Don't call the slow check_bytes() if the memory area is 64-bit aligned
memchr_inv compares contiguous 64-bit words with the 64-bit pattern as
much as possible. The outside of the region is checked by check_bytes()
that scans for each byte. Unfortunately, the first 64-bit word is
unexpectedly scanned by check_bytes() even if the memory area is aligned
to a 64-bit boundary.Both changes were originally suggested by Eric Dumazet.
Signed-off-by: Akinobu Mita
Suggested-by: Eric Dumazet
Cc: Brian Norris
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
After moving some core functions to led-core.c, led-class.c can be built
as module again.Signed-off-by: Bryan Wu
Acked-by: Richard Purdie
Acked-by: Linus Walleij
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Improve the readability by moving the code setting gen_config to one
place.[akpm@linux-foundation.org: fix some patch skew]
Signed-off-by: Axel Lin
Cc: Shreshtha Kumar Sahu
Cc: "Milo(Woogyom) Kim"
Cc: Richard Purdie
Acked-by: Linus Walleij
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Signed-off-by: Axel Lin
Cc: Peter Meerwald
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Use 'pdata' rather than 'pltfm' in lm3530_init_registers().
Signed-off-by: Milo(Woogyom) Kim
Cc: Linus Walleij
Cc: Richard Purdie
Cc: Axel Lin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
LM3530_ALS_ZONE_REG is read-only register.
Writing this register is not necessary.Signed-off-by: Milo(Woogyom) Kim
Cc: Linus Walleij
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
* add 'struct lm3530_pwm_data' in the platform data
The pwm data is the platform specific functions which generate the pwm.
The pwm data is only valid when brightness is pwm input mode.
Functions should be implemented by the pwm driver.
pwm_set_intensity() : set duty of pwm.
pwm_get_intensity() : get current the brightness.* brightness control by pwm
If the control mode is pwm, then brightness is changed by the duty of
pwm=. So pwm platform function should be called in lm3530_brightness_set().* do not update brightness register when pwm input mode
In pwm input mode, brightness register is not used.
If any value is updated in this register, then the led will be off.* when input mode is changed, set duty of pwm to 0 if unnecessary.
Signed-off-by: Milo(Woogyom) Kim
Cc: Linus Walleij
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
To get members of lm3530_data, use 'struct led_classdev' rather than
'struct i2c_client'.[akpm@linux-foundation.org: fix 80-column fixes more nicely]
Signed-off-by: Milo(Woogyom) Kim
Cc: Linus Walleij
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Only 7 bits are used for updating the brightness. (register address :
A0h) So the max_brightness property of lm3530 should be set to 127.On initializing registers, maximum initial brightness is limited to
'max_brightness'.Division-by-two is removed on updating the brightness. This arithmetic is
not necessary because the range of brightness is 0 ~ 127= .Signed-off-by: Milo(Woogyom) Kim
Cc: Linus Walleij
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Direct usage of the asm include has long been deprecated by the
introduction of gpiolib.Signed-off-by: Mark Brown
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Driver for the PCA9633 I2C chip supporting four LEDs and 255 brightness
levels.[akpm@linux-foundation.org: fix kcalloc() call]
[axel.lin@gmail.com: fix kcalloc parameters swapped]
Signed-off-by: Peter Meerwald
Signed-off-by: Axel Lin
Cc: Lars-Peter Clausen
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Saves ~50 bytes text and speeds things up.
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Fix it by assigning the lp5521_read return value.
Signed-off-by: srinidhi kasagar
Cc: Milo(Woogyom) Kim
Cc: Linus Walleij
Cc: Arun MURTHY
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
For better readability, values of LP5521_REG_ENABLE register were
redefined= . Additional definitions: LP5521_ENABLE_DEFAULT and
LP5521_ENABLE_RUN_PROGRAM= .Use definition rather than hard code value.
: 0x3F -> 'LP5521_CMD_DIRECT'Signed-off-by: Milo(Woogyom) Kim
Acked-by: Linus Walleij
Cc: Arun MURTHY
Cc: Srinidhi Kasagar
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The lp5521 has autonomous operation mode without external control.
Using lp5521_platform_data, various led patterns can be configurable.
For supporting this feature, new functions and device attribute are
added.Structure of lp5521_led_pattern: 3 channels are supported - red, green
and blue. Pattern(s) of each channel and numbers of pattern(s) are
defined in the pla= tform data. Pattern data are hexa codes which
include pattern commands such like set pwm, wait, ramp up/down, branch
and so on.Pattern mode functions:
* lp5521_clear_program_memory
Before running new led pattern, program memory should be cleared.
* lp5521_write_program_memory
Pattern data updated in the program memory via the i2c.
* lp5521_get_pattern
Get pattern from predefined in the platform data.
* lp5521_run_led_pattern
Stop current pattern or run new pattern.
Transition time is required between different operation mode.Device attribute - 'led_pattern': To load specific led pattern, new device
attribute is added.When the lp5521 driver is unloaded, stop current led pattern mode.
Documentation updated : description about how to define the led patterns
and example.[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Milo(Woogyom) Kim
Acked-by: Linus Walleij
Cc: Arun MURTHY
Cc: Srinidhi Kasagar
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The value of CONFIG register(Addr 08h) is configurable. For supporting
this feature, update_config is added in the platform data. If
'update_config' is not defined, the default value is 'LP5521_PWRSAVE_EN |
LP5521_CP_MODE_AUTO | LP5521_R_TO_BATT'.To define CONFIG register in the platform data, the bit definitions were
mo= ved to the header file.Documentation updated : description about 'update_config' and example.
Signed-off-by: Milo(Woogyom) Kim
Acked-by: Linus Walleij
Cc: Arun MURTHY
Cc: Srinidhi Kasagar
Cc: Richard Purdie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
