defconfigs: Enable and set Interactive CPU governor as default

Change-Id: Ie032e4bb88fa29eeb043d35ef6647e2d862cc908
ARM: Use -mcpu=cortex-a9 when targeting U8500 CPUs

Enable compiler optimizations specific to the Cortex-A9
processor when targeting U8500 CPUs. This is necessary
take advantage of the UDIV/SDIV instructions supported by
these processors. To accomplish this, we need to remove the
-march=armv7-a ISA restriction from the compiler options
because 'cortex-a9' is a superset of 'armv7-a'.

Change-Id: I9c0af3cb3fe1005f9f763e6a3f860f52af9741a4
arch/arm/Makefile: Enabled -pipe flag

-pipe uses pipes instead of temporary files for communication between the various stages of compilation. Thus, due to fewer R/W operations, the lifetime of an SSD is prolonged.

Change-Id: I1066f0d34e87798a6abda950911286029682abd6
defconfig: Rebrand so that it is easier to distinguish, and not confuse with other kernels

Change-Id: Idd27fc28be70af9ceff69484bd11ff6d1b94d768
ksm: check and skip page, if it is already scanned

From: Pradeep Sawlani <sawlani@amazon.com>

On system like Android where most of the process are forked
from parent w/o execve, KSM can scan same page multiple times
in one scan cycle. There is no advantage in scanning same page
multiple times for merging. During testing with Android, it was
observed around 60% pages are skipped for each scan cycle.

Change-Id: I0cf01802f0b4d61fcab92558beb9e1c660dc9a77
Link: http://lkml.kernel.org/r/CAMrOTPgBtANS_ryRjan0-dTL97U7eRvtf3dCsss=Kn+Uk89fuA@mail.gmail.com
Signed-off-by: Pradeep Sawlani <sawlani@amazon.com>

Signed-off-by: Paul Reioux <reioux@gmail.com>
lib/int_sqrt.c: optimize square root algorithm
Optimize the current version of the shift-and-subtract (hardware)
algorithm, described by John von Newmann[1] and Guy L Steele.

Iterating 1,000,000 times, perf shows for the current version:

 Performance counter stats for './sqrt-curr' (10 runs):

         27.170996 task-clock                #    0.979 CPUs utilized            ( +-  3.19% )
                 3 context-switches          #    0.103 K/sec                    ( +-  4.76% )
                 0 cpu-migrations            #    0.004 K/sec                    ( +-100.00% )
               104 page-faults               #    0.004 M/sec                    ( +-  0.16% )
        64,921,199 cycles                    #    2.389 GHz                      ( +-  0.03% )
        28,967,789 stalled-cycles-frontend   #   44.62% frontend cycles idle     ( +-  0.18% )
   <not supported> stalled-cycles-backend
       104,502,623 instructions              #    1.61  insns per cycle
                                             #    0.28  stalled cycles per insn  ( +-  0.00% )
        34,088,368 branches                  # 1254.587 M/sec                    ( +-  0.00% )
             4,901 branch-misses             #    0.01% of all branches          ( +-  1.32% )

       0.027763015 seconds time elapsed                                          ( +-  3.22% )

And for the new version:

Performance counter stats for './sqrt-new' (10 runs):

          0.496869 task-clock                #    0.519 CPUs utilized            ( +-  2.38% )
                 0 context-switches          #    0.000 K/sec
                 0 cpu-migrations            #    0.403 K/sec                    ( +-100.00% )
               104 page-faults               #    0.209 M/sec                    ( +-  0.15% )
           590,760 cycles                    #    1.189 GHz                      ( +-  2.35% )
           395,053 stalled-cycles-frontend   #   66.87% frontend cycles idle     ( +-  3.67% )
   <not supported> stalled-cycles-backend
           398,963 instructions              #    0.68  insns per cycle
                                             #    0.99  stalled cycles per insn  ( +-  0.39% )
            70,228 branches                  #  141.341 M/sec                    ( +-  0.36% )
             3,364 branch-misses             #    4.79% of all branches          ( +-  5.45% )

       0.000957440 seconds time elapsed                                          ( +-  2.42% )

Furthermore, this saves space in instruction text:

   text    data     bss     dec     hex filename
    111       0       0     111      6f lib/int_sqrt-baseline.o
     89       0       0      89      59 lib/int_sqrt.o

[1] http://en.wikipedia.org/wiki/First_Draft_of_a_Report_on_the_EDVAC

Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Reviewed-by: Jonathan Gonzalez <jgonzlez@linets.cl>
Tested-by: Jonathan Gonzalez <jgonzlez@linets.cl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Orig patch: torvalds/linux@30493cc#diff-afc36bd9416701066eeee37a1a93ecf1

Change-Id: Ifdf0ce9f7335ecd885f6f0ab1d6e5dd9d8958f0c
defconfig: Enable KSM_CHECK_PAGE

Change-Id: If8603b88bc052d9c1e54e78dd97dea8fc2ffaacf
block: Add ROW iosched
Backport by cocafe

Change-Id: I9d6e891ea99a748a588f720ff1e31aef2250dd1d
block: limit default readahead size for small devices

Linus reports a _really_ small & slow (505kB, 15kB/s) USB device,
on which blkid runs unpleasantly slow. He manages to optimize the blkid
reads down to 1kB+16kB, but still kernel read-ahead turns it into 48kB.

     lseek 0,    read 1024   => readahead 4 pages (start of file)
     lseek 1536, read 16384  => readahead 8 pages (page contiguous)

The readahead heuristics involved here are reasonable ones in general.
So it's good to fix blkid with fadvise(RANDOM), as Linus already did.

For the kernel part, Linus suggests:
  So maybe we could be less aggressive about read-ahead when the size of
  the device is small? Turning a 16kB read into a 64kB one is a big deal,
  when it's about 15% of the whole device!

This looks reasonable: smaller device tend to be slower (USB sticks as
well as micro/mobile/old hard disks).

Given that the non-rotational attribute is not always reported, we can
take disk size as a max readahead size hint. This patch uses a formula
that generates the following concrete limits:

        disk size    readahead size
     (scale by 4)      (scale by 2)
               1M                8k
               4M               16k
              16M               32k
              64M               64k
             256M              128k
        --------------------------- (*)
               1G              256k
               4G              512k
              16G             1024k
              64G             2048k
             256G             4096k
(*) Since the default readahead size is 128k, this limit only takes
effect for devices whose size is less than 256M.

The formula is determined on the following data, collected by script:

	#!/bin/sh

	# please make sure BDEV is not mounted or opened by others
	BDEV=sdb

	for rasize in 4 16 32 64 128 256 512 1024 2048 4096 8192
	do
		echo $rasize > /sys/block/$BDEV/queue/read_ahead_kb
		time dd if=/dev/$BDEV of=/dev/null bs=4k count=102400
	done
The principle is, the formula shall not limit readahead size to such a
degree that will impact some device's sequential read performance.

The Intel SSD is special in that its throughput increases steadily with
larger readahead size. However it may take years for Linux to increase
its default readahead size to 2MB, so we don't take it seriously in the
formula.

SSD 80G Intel x25-M SSDSA2M080 (reported by Li Shaohua)

	rasize	1st run		2nd run
	----------------------------------
	  4k	123 MB/s	122 MB/s
	 16k  	153 MB/s	153 MB/s
	 32k	161 MB/s	162 MB/s
	 64k	167 MB/s	168 MB/s
	128k	197 MB/s	197 MB/s
	256k	217 MB/s	217 MB/s
	512k	238 MB/s	234 MB/s
	  1M	251 MB/s	248 MB/s
	  2M	259 MB/s	257 MB/s
==>	  4M	269 MB/s	264 MB/s
	  8M	266 MB/s	266 MB/s
Note that ==> points to the readahead size that yields plateau throughput.

SSD 22G MARVELL SD88SA02 MP1F (reported by Jens Axboe)

	rasize  1st             2nd
	--------------------------------
	  4k     41 MB/s         41 MB/s
	 16k     85 MB/s         81 MB/s
	 32k    102 MB/s        109 MB/s
	 64k    125 MB/s        144 MB/s
	128k    183 MB/s        185 MB/s
	256k    216 MB/s        216 MB/s
	512k    216 MB/s        236 MB/s
	1024k   251 MB/s        252 MB/s
	  2M    258 MB/s        258 MB/s
==>       4M    266 MB/s        266 MB/s
	  8M    266 MB/s        266 MB/s
SSD 30G SanDisk SATA 5000

	  4k	29.6 MB/s	29.6 MB/s	29.6 MB/s
	 16k	52.1 MB/s	52.1 MB/s	52.1 MB/s
	 32k	61.5 MB/s	61.5 MB/s	61.5 MB/s
	 64k	67.2 MB/s	67.2 MB/s	67.1 MB/s
	128k	71.4 MB/s	71.3 MB/s	71.4 MB/s
	256k	73.4 MB/s	73.4 MB/s	73.3 MB/s
==>	512k	74.6 MB/s	74.6 MB/s	74.6 MB/s
	  1M	74.7 MB/s	74.6 MB/s	74.7 MB/s
	  2M	76.1 MB/s	74.6 MB/s	74.6 MB/s

USB stick 32G Teclast CoolFlash idVendor=1307, idProduct=0165

	  4k	7.9 MB/s 	7.9 MB/s 	7.9 MB/s
	 16k	17.9 MB/s	17.9 MB/s	17.9 MB/s
	 32k	24.5 MB/s	24.5 MB/s	24.5 MB/s
	 64k	28.7 MB/s	28.7 MB/s	28.7 MB/s
	128k	28.8 MB/s	28.9 MB/s	28.9 MB/s
==>	256k	30.5 MB/s	30.5 MB/s	30.5 MB/s
	512k	30.9 MB/s	31.0 MB/s	30.9 MB/s
	  1M	31.0 MB/s	30.9 MB/s	30.9 MB/s
	  2M	30.9 MB/s	30.9 MB/s	30.9 MB/s

USB stick 4G SanDisk  Cruzer idVendor=0781, idProduct=5151

	  4k	6.4 MB/s 	6.4 MB/s 	6.4 MB/s
	 16k	13.4 MB/s	13.4 MB/s	13.2 MB/s
	 32k	17.8 MB/s	17.9 MB/s	17.8 MB/s
	 64k	21.3 MB/s	21.3 MB/s	21.2 MB/s
	128k	21.4 MB/s	21.4 MB/s	21.4 MB/s
==>	256k	23.3 MB/s	23.2 MB/s	23.2 MB/s
	512k	23.3 MB/s	23.8 MB/s	23.4 MB/s
	  1M	23.8 MB/s	23.4 MB/s	23.3 MB/s
	  2M	23.4 MB/s	23.2 MB/s	23.4 MB/s

USB stick 2G idVendor=0204, idProduct=6025 SerialNumber: 08082005000113

	  4k	6.7 MB/s 	6.9 MB/s 	6.7 MB/s
	 16k	11.7 MB/s	11.7 MB/s	11.7 MB/s
	 32k	12.4 MB/s	12.4 MB/s	12.4 MB/s
   	 64k	13.4 MB/s	13.4 MB/s	13.4 MB/s
	128k	13.4 MB/s	13.4 MB/s	13.4 MB/s
==>	256k	13.6 MB/s	13.6 MB/s	13.6 MB/s
	512k	13.7 MB/s	13.7 MB/s	13.7 MB/s
	  1M	13.7 MB/s	13.7 MB/s	13.7 MB/s
	  2M	13.7 MB/s	13.7 MB/s	13.7 MB/s

64 MB, USB full speed (collected by Clemens Ladisch)
Bus 003 Device 003: ID 08ec:0011 M-Systems Flash Disk Pioneers DiskOnKey

	4KB:    139.339 s, 376 kB/s
	16KB:   81.0427 s, 647 kB/s
	32KB:   71.8513 s, 730 kB/s
==>	64KB:   67.3872 s, 778 kB/s
	128KB:  67.5434 s, 776 kB/s
	256KB:  65.9019 s, 796 kB/s
	512KB:  66.2282 s, 792 kB/s
	1024KB: 67.4632 s, 777 kB/s
	2048KB: 69.9759 s, 749 kB/s

An unnamed SD card (Yakui):

         4k     195.873 s,  5.5 MB/s
         8k     123.425 s,  8.7 MB/s
         16k    86.6425 s, 12.4 MB/s
         32k    66.7519 s, 16.1 MB/s
==>      64k    58.5262 s, 18.3 MB/s
         128k   59.3847 s, 18.1 MB/s
         256k   59.3188 s, 18.1 MB/s
         512k   59.0218 s, 18.2 MB/s

CC: Li Shaohua <shaohua.li@intel.com>
CC: Clemens Ladisch <clemens@ladisch.de>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Rik van Riel <riel@redhat.com>
Tested-by: Vivek Goyal <vgoyal@redhat.com>
Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
block: Fix auto readahead size

...with 128KB default readahead size, min() always select 128KB while 'size' is bigger than 128KB.

Signed-off-by: cocafe <cocafehj@gmail.com>
Makefile: Optimize with -O3 and flags

Change-Id: If2e5e555d59005b7304394a11ffa9f0a88cd96fd
cpufreq: interactive: Sync with android-3.0 branch

Change-Id: I0a2f1f1a0a36c4074aa361d60aefe8b84cba6326
cpufreq: interactive: Backport from android-3.4 branch

Change-Id: I0888d45dc628311f72154d2fb131b74342393ba8
Makefile: Remove unnecessary flag

Change-Id: Ia397401bf25703852af6ada45f2382bb07b240b8
defconfig: remove useless governors

Change-Id: I748538b4eec789adb7f8cfc186ae3f5fbfd4e982
Revert "Add Simple I/O scheduler"

This reverts commit 4ad090e92e9836507c6cbbd50a9c797b450a752a.

Change-Id: I8048a2b22024de9e2a3be425e8da48f15a83944a
block: Reserve only one queue tag for sync IO if only 3 tags are available

In case a device has three tags available we still reserve two of them
for sync IO. That leaves only a single tag for async IO such as
writeback from flusher thread which results in poor performance.

Allow async IO to consume two tags in case queue has three tag availabe
to get a decent async write performance.

This patch improves streaming write performance on a machine with such disk
from ~21 MB/s to ~52 MB/s. Also postmark throughput in presence of
streaming writer improves from 8 to 12 transactions per second so sync
IO doesn't seem to be harmed in presence of heavy async writer.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
deadline: Allow 0ms deadline latency, increase the read speed

Change a timer compare from after to after-equals, thus allowing
0 timeout and making deadline schedule FIFO.

Signed-off-by: xiaobing tu <xiaobing.tu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
defconfig: Make ROW the default scheduler

Change-Id: I3b69af9b9de8ed4c826bbdafc1675b7f4d79cdd6
ARM: decompressor: Enable unaligned memory access for v6 and above

Modern GCC can generate code which makes use of the CPU's native
unaligned memory access capabilities.  This is useful for the C
decompressor implementations used for unpacking compressed kernels.

This patch disables alignment faults and enables the v6 unaligned
access model on CPUs which support these features (i.e., v6 and
later), allowing full unaligned access support for C code in the
decompressor.

The decompressor C code must not be built to assume that unaligned
access works if support for v5 or older platforms is included in
the kernel.

For correct code generation, C decompressor code must always use
the get_unaligned and put_unaligned accessors when dealing with
unaligned pointers, regardless of this patch.

Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>