openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity
linux/drivers
History
Markus Pargmann 4ce78a838c can: c_can: Speed up rx_poll function 
This patch speeds up the rx_poll function by reducing the number of
register reads.

Replace the 32bit register read by a 16bit register read. Currently
the 32bit register read is implemented by using 2 16bit reads. This is
inefficient as we only use the lower 16bit in rx_poll.

The for loop reads the pending interrupts in every iteration. This
leads up to 16 reads of pending interrupts. The patch introduces a new
outer loop to read the pending interrupts as long as 'quota' is above 0.
This reduces the total number of reads.

The third change is to replace the for-loop by a ffs loop.

Tested on AM335x. I removed all 'static' and 'inline' from c_can.c to
see the timings for all functions. I used the function tracer with
trace_stats.

125kbit:
  Function                               Hit    Time            Avg             s^2
  --------                               ---    ----            ---             ---
  c_can_do_rx_poll                     63960    10168178 us     158.977 us      1493056 us
With patch:
  c_can_do_rx_poll                     63941    3764057 us      58.867 us       776162.2 us

1Mbit:
  Function                               Hit    Time            Avg             s^2
  --------                               ---    ----            ---             ---
  c_can_do_rx_poll                     69489    30049498 us     432.435 us      9271851 us
With patch:
  c_can_do_rx_poll                    207109    24322185 us     117.436 us      171469047 us

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
 		2013-12-17 11:47:19 +01:00
..
accessibility
…
acpi Merge branch 'acpica' 2013-11-27 01:03:27 +01:00
amba DMA-API: amba: get rid of separate dma_mask 2013-10-31 14:48:38 +00:00
ata ATA: Fix port removal ordering 2013-11-27 13:55:16 -05:00
atm atm: solos-pci: remove unnecessary pci_set_drvdata() 2013-12-10 22:31:33 -05:00
auxdisplay framebuffer: Use fb_<level> 2013-10-29 12:53:07 +02:00
base More ACPI and power management updates for 3.13-rc1 2013-11-20 13:25:04 -08:00
bcma bcma: pci: remove unnecessary pci_set_drvdata() 2013-12-05 14:56:39 -05:00
block kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS cleanly 2013-11-21 16:42:27 -08:00
bluetooth Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth 2013-11-05 15:58:21 -05:00
bus Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-arm 2013-11-14 08:51:29 +09:00
cdrom
…
char Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2013-11-23 16:18:25 -08:00
clk Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-11-15 16:47:22 -08:00
clocksource
…
connector connector: improved unaligned access error fix 2013-11-14 17:19:20 -05:00
cpufreq Merge branch 'pm-cpufreq' 2013-11-27 01:03:43 +01:00
cpuidle ACPI and power management updates for 3.13-rc1 2013-11-14 13:41:48 +09:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2013-11-23 16:18:25 -08:00
dca
…
devfreq Merge branch 'pm-devfreq' 2013-11-07 19:24:20 +01:00
dio
…
dma Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2013-11-20 13:20:24 -08:00
edac Merge branch 'linux_next' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-edac 2013-11-18 14:51:52 -08:00
eisa
…
extcon
…
firewire tree-wide: use reinit_completion instead of INIT_COMPLETION 2013-11-15 09:32:21 +09:00
firmware Merge branch 'for-linus-dma-masks' of git://git.linaro.org/people/rmk/linux-arm 2013-11-14 07:55:21 +09:00
fmc
…
gpio GPIO fixes for the v3.13 series: 2013-11-28 09:57:46 -08:00
gpu drm/qxl: fix memory leak in release list handling 2013-11-29 08:36:15 +10:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid 2013-11-27 20:41:54 -08:00
hsi
…
hv
…
hwmon Merge branch 'acpica' 2013-11-27 01:03:27 +01:00
hwspinlock
…
i2c Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2013-11-29 09:55:13 -08:00
ide More ACPI and power management updates for 3.13-rc1 2013-11-20 13:25:04 -08:00
idle Merge branch 'pm-cpuidle' 2013-11-19 01:06:28 +01:00
iio First round of fixes for IIO in the 3.13 cycle. 2013-11-25 12:50:11 -08:00
infiniband Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2013-11-22 10:52:03 -08:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2013-11-24 10:45:29 -08:00
iommu Don't try to compile shmobile-iommu outside of ARM 2013-11-15 18:57:42 -08:00
ipack
…
irqchip Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-12-02 10:15:39 -08:00
isdn net: rework recvmsg handler msg_name and msg_namelen logic 2013-11-20 21:52:30 -05:00
leds
…
lguest x86, asmlinkage, lguest: Pass in globals into assembler statement 2013-11-07 12:13:05 +10:30
macintosh powerpc/windfarm: Fix XServe G5 fan control Makefile issue 2013-11-27 11:35:47 +11:00
mailbox
…
md md/raid5: fix newly-broken locking in get_active_stripe. 2013-11-28 11:00:15 +11:00
media Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2013-11-20 13:20:24 -08:00
memory
…
memstick tree-wide: use reinit_completion instead of INIT_COMPLETION 2013-11-15 09:32:21 +09:00
message drivers/message/i2o/driver.c: add missing destroy_workqueue() on error in i2o_driver_register() 2013-11-13 12:09:26 +09:00
mfd Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-11-15 16:47:22 -08:00
misc Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2013-11-20 13:20:24 -08:00
mmc More ACPI and power management updates for 3.13-rc1 2013-11-20 13:25:04 -08:00
mtd Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2013-11-20 13:20:24 -08:00
net can: c_can: Speed up rx_poll function 2013-12-17 11:47:19 +01:00
nfc
…
ntb NTB driver bug fixes to address a missed call to pci_enable_msix, 2013-11-26 11:15:12 -08:00
nubus
…
of net: of_mdio: parse "max-speed" property to set PHY supported features 2013-12-06 14:57:21 -05:00
oprofile
…
parisc
…
parport Kconfig cleanups for v3.13 2013-11-15 14:05:15 -08:00
pci PCI / tg3: Give up chip reset and carrier loss handling if PCI device is not present 2013-12-02 16:01:49 -05:00
pcmcia DeviceTree updates for 3.13. This is a bit larger pull request than 2013-11-12 16:52:17 +09:00
phy
…
pinctrl pinctrl: single: call pcs_soc->rearm() whenever IRQ mask is changed 2013-11-14 10:43:17 -08:00
platform sony-laptop: do not scribble keyboard backlight registers on resume 2013-11-26 13:03:36 +09:00
pnp ACPI: Eliminate the DEVICE_ACPI_HANDLE() macro 2013-11-14 23:17:21 +01:00
power Highlights: 2013-11-18 15:35:09 -08:00
powercap PowerCap: Fix build error with option -Werror=format-security 2013-11-05 02:36:57 +01:00
pps drivers/pps/clients/pps-gpio.c: remove redundant of_match_ptr 2013-11-13 12:09:35 +09:00
ps3
…
ptp
…
pwm pwm: samsung: Fix kernel warning while unexporting a channel 2013-11-01 11:17:57 +01:00
rapidio
…
regulator Merge remote-tracking branch 'regulator/fix/pfuze100' into regulator-linus 2013-11-24 14:02:50 +00:00
remoteproc
…
reset
…
rpmsg
…
rtc ARM: drivers/rtc/rtc-at91rm9200.c: disable interrupts at shutdown 2013-11-21 16:42:27 -08:00
s390 s390/dasd: validate request size before building CCW/TCW request 2013-11-20 09:04:54 +01:00
sbus
…
scsi Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-12-02 10:09:07 -08:00
sfi
…
sh
…
sn
…
spi Merge remote-tracking branches 'spi/fix/bcm2835', 'spi/fix/bcm63xx', 'spi/fix/mpc512x-psc', 'spi/fix/mxs', 'spi/fix/pxa2xx', 'spi/fix/qspi', 'spi/fix/rspi' and 'spi/fix/txx9' into spi-linus 2013-11-28 11:31:35 +00:00
ssb
…
staging Staging: tidspbridge: disable driver 2013-11-27 09:32:49 -08:00
target Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2013-11-22 10:52:03 -08:00
tc
…
thermal Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-11-19 15:50:47 -08:00
tty Revert "n_gsm: race between ld close and gsmtty open" 2013-11-25 18:30:21 -08:00
uio drivers/uio/uio_pruss.c: use gen_pool_dma_alloc() to allocate sram memory 2013-11-13 12:09:23 +09:00
usb Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2013-11-22 10:52:03 -08:00
uwb Driver Core / sysfs patches for 3.13-rc1 2013-11-07 11:42:15 +09:00
vfio
…
vhost vhost: remove the dead branch 2013-12-06 15:22:05 -05:00
video ARM: SoC fixes for 3.13 merge window 2013-11-16 12:45:55 -08:00
virt
…
virtio Nothing really exciting: some groundwork for changing virtio endian, and 2013-11-15 13:28:47 +09:00
vlynq
…
vme
…
w1 drivers/w1/masters/w1-gpio.c: use dev_get_platdata() 2013-11-15 09:32:21 +09:00
watchdog watchdog: w83627hf: Use helper functions to access superio registers 2013-11-18 21:34:19 +01:00
xen Bug-fixes: 2013-12-02 10:12:01 -08:00
zorro
…
Kconfig ACPI and power management updates for 3.13-rc1 2013-11-14 13:41:48 +09:00
Makefile ACPI and power management updates for 3.13-rc1 2013-11-14 13:41:48 +09:00