dts: lm3630: lower min brightness to 1

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
dts: lm3630: lower blmap for lower brightness levels

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
switch do_fsync() to fget_light()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
readahead: make context readahead more conservative

This helps performance on moderately dense random reads on SSD.

Transaction-Per-Second numbers provided by Taobao:

		QPS	case
		-------------------------------------------------------
		7536	disable context readahead totally
w/ patch:	7129	slower size rampup and start RA on the 3rd read
		6717	slower size rampup
w/o patch:	5581	unmodified context readahead

Before, readahead will be started whenever reading page N+1 when it happen
to read N recently.  After patch, we'll only start readahead when *three*
random reads happen to access pages N, N+1, N+2.  The probability of this
happening is extremely low for pure random reads, unless they are very
dense, which actually deserves some readahead.

Also start with a smaller readahead window.  The impact to interleaved
sequential reads should be small, because for a long run stream, the the
small readahead window rampup phase is negletable.

The context readahead actually benefits clustered random reads on HDD
whose seek cost is pretty high.  However as SSD is increasingly used for
random read workloads it's better for the context readahead to concentrate
on interleaved sequential reads.

Another SSD rand read test from Miao

        # file size:        2GB
        # read IO amount: 625MB
        sysbench --test=fileio          \
                --max-requests=10000    \
                --num-threads=1         \
                --file-num=1            \
                --file-block-size=64K   \
                --file-test-mode=rndrd  \
                --file-fsync-freq=0     \
                --file-fsync-end=off    run

shows the performance of btrfs grows up from 69MB/s to 121MB/s, ext4 from
104MB/s to 121MB/s.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Tested-by: Tao Ma <tm@tao.ma>
Tested-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
nohz: Reduce overhead under high-freq idling patterns

One testbox of mine (Intel Nehalem, 16-way) uses MWAIT for its idle routine,
which apparently can break out of its idle loop rather frequently, with
high frequency.

In that case NO_HZ_FULL=y kernels show high ksoftirqd overhead and constant
context switching, because tick_nohz_stop_sched_tick() will, if
delta_jiffies == 0, mis-identify this as a timer event - activating the
TIMER_SOFTIRQ, which wakes up ksoftirqd.

Fix this by treating delta_jiffies == 0 the same way we treat other short
wakeups, delta_jiffies == 1.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
softirq: reduce latencies

In various network workloads, __do_softirq() latencies can be up
to 20 ms if HZ=1000, and 200 ms if HZ=100.

This is because we iterate 10 times in the softirq dispatcher,
and some actions can consume a lot of cycles.

This patch changes the fallback to ksoftirqd condition to :

- A time limit of 2 ms.
- need_resched() being set on current task

When one of this condition is met, we wakeup ksoftirqd for further
softirq processing if we still have pending softirqs.

Using need_resched() as the only condition can trigger RCU stalls,
as we can keep BH disabled for too long.

I ran several benchmarks and got no significant difference in
throughput, but a very significant reduction of latencies (one order
of magnitude) :

In following bench, 200 antagonist "netperf -t TCP_RR" are started in
background, using all available cpus.

Then we start one "netperf -t TCP_RR", bound to the cpu handling the NIC
IRQ (hard+soft)

Before patch :

# netperf -H 7.7.7.84 -t TCP_RR -T2,2 -- -k
RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY
MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET
to 7.7.7.84 () port 0 AF_INET : first burst 0 : cpu bind
RT_LATENCY=550110.424
MIN_LATENCY=146858
MAX_LATENCY=997109
P50_LATENCY=305000
P90_LATENCY=550000
P99_LATENCY=710000
MEAN_LATENCY=376989.12
STDDEV_LATENCY=184046.92

After patch :

# netperf -H 7.7.7.84 -t TCP_RR -T2,2 -- -k
RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY
MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET
to 7.7.7.84 () port 0 AF_INET : first burst 0 : cpu bind
RT_LATENCY=40545.492
MIN_LATENCY=9834
MAX_LATENCY=78366
P50_LATENCY=33583
P90_LATENCY=59000
P99_LATENCY=69000
MEAN_LATENCY=38364.67
STDDEV_LATENCY=12865.26

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Miller <davem@davemloft.net>
Cc: Tom Herbert <therbert@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
ext4: speed up truncate/unlink by not using bforget() unless needed

Do not iterate over data blocks scanning for bh's to forget as they're
never exist. This improves time taken by unlink / truncate syscall.
Tested by continuously truncating file that is being written by dd.
Another test is rm -rf of linux tree while tar unpacks it. With
ordered data mode condition unlikely(!tbh) was always met in
ext4_free_blocks. With journal data mode tbh was found only few times,
so optimisation is also possible.

Unlinking fallocated 60G file after doing sync && echo 3 >
/proc/sys/vm/drop_caches && time rm --help

X86 before (linux 3.6-rc4):
# time rm -f test1
real    0m2.710s
user    0m0.000s
sys     0m1.530s

X86 after:
# time rm -f test1
real    0m0.644s
user    0m0.003s
sys     0m0.060s

MIPS before (linux 2.6.37):
# time rm -f test1
real    0m 4.93s
user    0m 0.00s
sys     0m 4.61s

MIPS after:
# time rm -f test1
real    0m 0.16s
user    0m 0.00s
sys     0m 0.06s

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrey Sidorov <qrxd43@motorola.com>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
af_unix: speedup /proc/net/unix /proc/net/unix has quadratic behavior, and can hold unix_table_lock for a while if high number of unix sockets are alive. (90 ms for 200k sockets...)

We already have a hash table, so its quite easy to use it.

Problem is unbound sockets are still hashed in a single hash slot
(unix_socket_table[UNIX_HASH_TABLE])

This patch also spreads unbound sockets to 256 hash slots, to speedup
both /proc/net/unix and unix_diag.

Time to read /proc/net/unix with 200k unix sockets :
(time dd if=/proc/net/unix of=/dev/null bs=4k)

before : 520 secs
after : 2 secs

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
net: loopback: set default mtu to 64K

loopback current mtu of 16436 bytes allows no more than 3 MSS TCP
segments per frame, or 48 Kbytes. Changing mtu to 64K allows TCP
stack to build large frames and significantly reduces stack overhead.

Performance boost on bulk TCP transferts can be up to 30 %, partly
because we now have one ACK message for two 64KB segments, and a lower
probability of hitting /proc/sys/net/ipv4/tcp_reordering default limit.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
ASoc: Reduce number of periods in low latency driver.

- Reduce number of periods to 2 from 4.

Signed-off-by: SathishKumar Mani <smani@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
ASoc: msm: Increase max buffer size to 4k for lowlatency playback

- Small buffersize is resulting in scheduling issues.
- Increase max buffer size so that user space can
  configure large buffer size to avoid scheduling
  issues.

bug-id: 6865729
Signed-off-by: SathishKumar Mani <smani@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
ASoC: msm: Reduce min buffer size for low latency

The current low latency driver has 512 bytes as
the min buffer size threshold. With this reducing
the playback time to lower values is not possible.
Setting it to 128 bytes gives us more room
to try out lower buffer sizes from the user space

Signed-off-by: Alexy Joseph <alexyj@codeaurora.org>
Signed-off-by: Mekala Natarajan <mekalan@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
ASoC: msm: Change QOS value for low latency path

There were variations in the time taken to
return from each write. This was due
to the delay in switching in and out of
power collapse. To manage this set QOS
value to 1ms so that the core has enough
time to wake up from power collapse

Signed-off-by: Alexy Joseph <alexyj@codeaurora.org>
Signed-off-by: Mekala Natarajan <mekalan@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
USB: f_mtp: Set maximum burst value to two for superspeed mode

Currently burst value is set to zero for superspeed in mtp driver.
MTP throughput can be improved by setting max burst vlaue to non
zero value in superspeed mode. Hence set max burst vlaue to two
for both IN and OUT bulk endpoints in superspeed mode.

CRs-Fixed: 532070
Change-Id: Ib78b8fec5d1ab934f4d4ec80b7e008149707ce0f
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
USB: gadget: rndis: Optimize tx path for better performance

Current rndis header addition and aggregation steps:
1. Increase skb headroom by size of rndis header.
2. Copy skb data with newly created skb having more headroom.
3. Create and add rndis header with it.
4. Again copy skb data with usb request buffer for aggregation purpose.

New optimized steps :
1. Create and copy rndis header directly with usb request buffer
2. Copy skb data with usb request buffer

Above new steps avoids cpu intensive skb operations which reduces CPU
usage and provide better throughput.

This change also assigns completion handle with usb request at the time
of usb request creation instead of assigning everytime before queueing
usb request.

CRs-Fixed: 551363
Change-Id: Ifc64d6a8573f6a24e28c73ef9a19b62649e171cd
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>
ASoC: msm: Add 24 bit support to Primary MI2S TX

Add 24 bit support to Primary MI2S Tx. Add
capability to specify bits per sample to DSP.

Change-Id: I928f37c7b76ffea735365b164d52ceabd88e77e6
Signed-off-by: Damir Didjusto <damird@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>
Signed-off-by: aatjitra <aatjitra@gmail.com>