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27c7acf220
linux/drivers
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Johan Hovold 27c7acf220 USB: serial: reimplement generic fifo-based writes 
Reimplement fifo-based writes in the generic driver using a multiple
pre-allocated urb scheme.

In contrast to multi-urb writes, no allocations (of urbs or buffers) are
made during run-time and there is less pressure on the host stack
queues as currently only two urbs are used (implementation is generic
and can handle more than two urbs as well, though).

Initial tests using ftdi_sio show that the implementation achieves the
same (maximum) throughput at high baudrates as multi-urb writes. The CPU
usage is much lower than for multi-urb writes for small write requests
and only slightly higher for large (e.g. 2k) requests (due to extra copy
via fifo?).

Also outperforms multi-urb writes for small write requests on an
embedded arm-9 system, where multi-urb writes are CPU-bound at high
baudrates (perf reveals that a lot of time is spent in the host stack
enqueue function -- could perhaps be a bug as well).

Keeping the original write_urb, buffer and flag for now as there are
other drivers depending on them.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-05-20 13:21:42 -07:00
..
accessibility
acpi ACPI: sleep: eliminate duplicate entries in acpisleep_dmi_table[] 2010-05-11 10:07:53 -07:00
amba
ata pata_pcmcia / ide-cs: Fix bad hashes for Transcend and kingston IDs 2010-05-05 14:48:48 -04:00
atm include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
auxdisplay include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
base Revert "memory-hotplug: add 0x prefix to HEX block_size_bytes" 2010-04-09 10:05:33 -07:00
block Merge branch 'for-jens' of git://git.drbd.org/linux-2.6-drbd into for-linus 2010-05-04 08:48:53 +02:00
bluetooth include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
cdrom
char tty: Fix unbalanced BKL handling in error path 2010-05-13 12:10:56 -07:00
clocksource include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
connector include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
cpufreq Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq 2010-04-24 11:35:21 -07:00
cpuidle cpuidle: Fix incorrect optimization 2010-05-09 18:35:36 -07:00
crypto include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
dca include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
dio
dma Merge branch 'sh/for-2.6.34' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6 2010-05-06 08:37:39 -07:00
edac edac, mce: Fix wrong mask and macro usage 2010-04-30 10:15:39 -07:00
eisa
firewire Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 2010-04-22 12:54:54 -07:00
firmware Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip 2010-04-07 11:02:23 -07:00
gpio it8761e_gpio: fix bug in gpio numbering 2010-05-11 17:33:41 -07:00
gpu drivers/gpu/drm/i915/i915_irq.c:i915_error_object_create(): use correct kmap-atomic slot 2010-05-11 17:33:42 -07:00
hid USB: rename usb_buffer_alloc() and usb_buffer_free() users 2010-05-20 13:21:38 -07:00
hwmon Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging 2010-05-11 17:38:04 -07:00
i2c i2c-core: Use per-adapter userspace device lists 2010-05-04 11:09:28 +02:00
ide pata_pcmcia / ide-cs: Fix bad hashes for Transcend and kingston IDs 2010-05-05 14:48:48 -04:00
idle include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
ieee1394 include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
ieee802154
infiniband Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband 2010-04-09 11:53:06 -07:00
input USB: rename usb_buffer_alloc() and usb_buffer_free() users 2010-05-20 13:21:38 -07:00
isdn Fix ISDN/Gigaset build failure 2010-04-19 11:53:17 -07:00
leds include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
lguest lguest: stop using KVM hypercall mechanism 2010-04-14 21:43:56 +09:30
macintosh device_attributes: add sysfs_attr_init() for dynamic attributes 2010-04-07 08:38:03 -07:00
mca
md md: restore ability of spare drives to spin down. 2010-05-07 21:10:57 +10:00
media USB: remove leftover references to udev->autosuspend_disabled 2010-05-20 13:21:40 -07:00
memstick include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
message include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
mfd mfd: Clean up after WM83xx AUXADC interrupt if it arrives late 2010-05-13 12:58:55 +02:00
misc VMware Balloon driver 2010-04-24 11:31:26 -07:00
mmc mmc: at91_mci: modify cache flush routines 2010-05-15 12:48:10 -07:00
mtd [MTD] Remove zero-length files mtdbdi.c and internal.ho 2010-05-05 15:25:12 -04:00
net USB: remove leftover references to udev->autosuspend_disabled 2010-05-20 13:21:40 -07:00
nubus include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
of of: check for IS_ERR() 2010-04-28 01:07:29 -06:00
oprofile include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
parisc include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
parport include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
pci Revert "PCI: update bridge resources to get more big ranges in PCI assign unssigned" 2010-05-12 18:39:45 -07:00
pcmcia Merge branch 'urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2010-05-07 14:11:09 -07:00
platform eeepc-laptop: add missing sparse_keymap_free 2010-04-23 15:23:21 -04:00
pnp Merge branches 'bugzilla-14337', 'bugzilla-14998', 'bugzilla-15407', 'bugzilla-15903' and 'misc-2.6.34' into release 2010-05-06 22:04:31 -04:00
power include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
pps include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
ps3 include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
rapidio
regulator regulator: fix enabling regulator issue on max8925 2010-04-28 15:24:34 +01:00
rtc rtc-mxc: multiple fixes in rtc-mxc probe method 2010-04-07 08:38:05 -07:00
s390 [S390] dasd: fix race between tasklet and dasd_sleep_on 2010-05-12 09:32:26 +02:00
sbus include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
scsi [SCSI] Retry commands with UNIT_ATTENTION sense codes to fix ext3/ext4 I/O error 2010-05-05 12:15:57 -04:00
serial serial: imx.c: fix CTS trigger level lower to avoid lost chars 2010-05-13 12:10:56 -07:00
sfi
sh include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
sn include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
spi omap2_mcspi: small fixes of output data format 2010-04-28 01:25:43 -06:00
ssb MIPS: Fix SSB PCIcore IO resource management 2010-04-12 17:26:14 +01:00
staging USB: remove URB_NO_SETUP_DMA_MAP 2010-05-20 13:21:40 -07:00
tc include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
telephony
thermal drivers/thermal/thermal_sys.c: fix 'key f70f4b50 not in .data' in thermal_sys 2010-04-07 08:38:03 -07:00
uio include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
usb USB: serial: reimplement generic fifo-based writes 2010-05-20 13:21:42 -07:00
uwb include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
vhost vhost: fix barrier pairing 2010-05-12 18:04:04 +03:00
video fbdev: bfin-t350mcqb-fb: fix fbmem allocation with blanking lines 2010-05-11 17:33:42 -07:00
virtio virtio: Fix GFP flags passed from the virtio balloon driver 2010-04-22 07:34:05 -07:00
vlynq include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
w1 w1: fix omap 1-wire driver compilation 2010-04-24 11:31:25 -07:00
watchdog USB: rename usb_buffer_alloc() and usb_buffer_free() users 2010-05-20 13:21:38 -07:00
xen include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
zorro
Kconfig
Makefile virtio: initialize earlier 2010-05-07 14:01:17 -07:00