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| author | Arnd Bergmann <arnd@arndb.de> | 2014-03-17 15:17:07 +0100 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2014-03-17 15:17:07 +0100 |
| commit | 38edc2da5014e70e46a724d97c3ef3dde106331b (patch) | |
| tree | 590499bacd062e8dd74c6f05a7d811dd714a2d70 /net/sched/sch_pie.c | |
| parent | 937b5991ca7717ceba99014f2ad3f51c85cdb9ad (diff) | |
| parent | 28b191118c11719bb27db621425a70be28a40e08 (diff) | |
Merge tag 'omap-for-v3.15/dt-overo-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into next/dt
Updates to the .dts files to support more Gumstix boards.
These are sent separately from the rest of the .dts changes
as these depend on the fixes merged into v3.14-rc4, and
needed a bit more time to get updated on the fixes.
* tag 'omap-for-v3.15/dt-overo-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
ARM: dts: Add support for the Overo Summit
ARM: dts: Add support for the Overo Chestnut43
ARM: dts: Add support for the Overo Alto35
ARM: dts: Add support for the Overo Gallop43
ARM: dts: Add support for the Overo Palo43
ARM: dts: overo: Add LIS33DE accelerometer
ARM: dts: overo: Create a file for common Gumstix peripherals
ARM: dts: overo: Push uart3 pinmux down to expansion board
ARM: dts: omap3-tobi: Add AT24C01 EEPROM
ARM: dts: omap3-tobi: Use include file omap-gpmc-smsc9221
ARM: dts: omap: Add common file for SMSC9221
ARM: dts: omap3-overo: Add HSUSB PHY
ARM: dts: omap3-overo: Enable WiFi/BT combo
ARM: dts: omap3-overo: Add missing pinctrl
ARM: dts: omap3-tobi: Add missing pinctrl
ARM: dts: overo: reorganize include files
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Conflicts:
arch/arm/boot/dts/omap3-overo.dtsi
Diffstat (limited to 'net/sched/sch_pie.c')
| -rw-r--r-- | net/sched/sch_pie.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/net/sched/sch_pie.c b/net/sched/sch_pie.c index a255d0200a59..fefeeb73f15f 100644 --- a/net/sched/sch_pie.c +++ b/net/sched/sch_pie.c @@ -15,6 +15,11 @@ * * ECN support is added by Naeem Khademi <naeemk@ifi.uio.no> * University of Oslo, Norway. + * + * References: + * IETF draft submission: http://tools.ietf.org/html/draft-pan-aqm-pie-00 + * IEEE Conference on High Performance Switching and Routing 2013 : + * "PIE: A * Lightweight Control Scheme to Address the Bufferbloat Problem" */ #include <linux/module.h> @@ -36,7 +41,7 @@ struct pie_params { psched_time_t target; /* user specified target delay in pschedtime */ u32 tupdate; /* timer frequency (in jiffies) */ u32 limit; /* number of packets that can be enqueued */ - u32 alpha; /* alpha and beta are between -4 and 4 */ + u32 alpha; /* alpha and beta are between 0 and 32 */ u32 beta; /* and are used for shift relative to 1 */ bool ecn; /* true if ecn is enabled */ bool bytemode; /* to scale drop early prob based on pkt size */ @@ -326,10 +331,16 @@ static void calculate_probability(struct Qdisc *sch) if (qdelay == 0 && qlen != 0) update_prob = false; - /* Add ranges for alpha and beta, more aggressive for high dropping - * mode and gentle steps for light dropping mode - * In light dropping mode, take gentle steps; in medium dropping mode, - * take medium steps; in high dropping mode, take big steps. + /* In the algorithm, alpha and beta are between 0 and 2 with typical + * value for alpha as 0.125. In this implementation, we use values 0-32 + * passed from user space to represent this. Also, alpha and beta have + * unit of HZ and need to be scaled before they can used to update + * probability. alpha/beta are updated locally below by 1) scaling them + * appropriately 2) scaling down by 16 to come to 0-2 range. + * Please see paper for details. + * + * We scale alpha and beta differently depending on whether we are in + * light, medium or high dropping mode. */ if (q->vars.prob < MAX_PROB / 100) { alpha = |