Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-14 Thread Brian Adamson
Hi Michael, I really appreciate your time in helping us dive into this issue. Below, you had suggested to "limit the speed of tun interface using a non work conserving disc" and matching the rate of the backend device. Unfortunately, many backend devices (whether real devices or ones we are

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-14 Thread Brian Adamson
Hi Michael, I really appreciate your time in helping us dive into this issue. Below, you had suggested to limit the speed of tun interface using a non work conserving disc and matching the rate of the backend device. Unfortunately, many backend devices (whether real devices or ones we are

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-13 Thread Michael S. Tsirkin
On Sun, Apr 13, 2014 at 09:28:51PM -0400, Steven Galgano wrote: > On 04/13/2014 10:14 AM, Michael S. Tsirkin wrote: > > > > Steven, Brian, > > > > thanks for reporting this issue. > > Please see my comments below. > > > > On Fri, Apr 11, 2014 at 12:41:42PM -0400, Brian Adamson wrote: > >> To

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-13 Thread Steven Galgano
On 04/13/2014 10:14 AM, Michael S. Tsirkin wrote: > > Steven, Brian, > > thanks for reporting this issue. > Please see my comments below. > > On Fri, Apr 11, 2014 at 12:41:42PM -0400, Brian Adamson wrote: >> To weigh in on the desire to have support (at least as an optional behavior) >> for

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-13 Thread Michael S. Tsirkin
Hi Steven, On Thu, Apr 10, 2014 at 09:42:19PM -0400, Steven Galgano wrote: > On 04/10/2014 06:29 AM, Michael S. Tsirkin wrote: > > On Wed, Apr 09, 2014 at 10:19:40PM -0400, Steven Galgano wrote: > >> Add tuntap flow control support for use by back pressure routing > >> protocols. Setting the new

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-13 Thread Michael S. Tsirkin
Steven, Brian, thanks for reporting this issue. Please see my comments below. On Fri, Apr 11, 2014 at 12:41:42PM -0400, Brian Adamson wrote: > To weigh in on the desire to have support (at least as an optional behavior) > for the legacy flow control behavior, there are many existing uses of

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-13 Thread Michael S. Tsirkin
Steven, Brian, thanks for reporting this issue. Please see my comments below. On Fri, Apr 11, 2014 at 12:41:42PM -0400, Brian Adamson wrote: To weigh in on the desire to have support (at least as an optional behavior) for the legacy flow control behavior, there are many existing uses of it.

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-13 Thread Michael S. Tsirkin
Hi Steven, On Thu, Apr 10, 2014 at 09:42:19PM -0400, Steven Galgano wrote: On 04/10/2014 06:29 AM, Michael S. Tsirkin wrote: On Wed, Apr 09, 2014 at 10:19:40PM -0400, Steven Galgano wrote: Add tuntap flow control support for use by back pressure routing protocols. Setting the new

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-13 Thread Steven Galgano
On 04/13/2014 10:14 AM, Michael S. Tsirkin wrote: Steven, Brian, thanks for reporting this issue. Please see my comments below. On Fri, Apr 11, 2014 at 12:41:42PM -0400, Brian Adamson wrote: To weigh in on the desire to have support (at least as an optional behavior) for the legacy

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-13 Thread Michael S. Tsirkin
On Sun, Apr 13, 2014 at 09:28:51PM -0400, Steven Galgano wrote: On 04/13/2014 10:14 AM, Michael S. Tsirkin wrote: Steven, Brian, thanks for reporting this issue. Please see my comments below. On Fri, Apr 11, 2014 at 12:41:42PM -0400, Brian Adamson wrote: To weigh in on the

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-11 Thread Brian Adamson
To weigh in on the desire to have support (at least as an optional behavior) for the legacy flow control behavior, there are many existing uses of it. Many these are related to experimental purposes where the tuntap driver can be used (with a little user space code) as a surrogate for a

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-11 Thread Brian Adamson
To weigh in on the desire to have support (at least as an optional behavior) for the legacy flow control behavior, there are many existing uses of it. Many these are related to experimental purposes where the tuntap driver can be used (with a little user space code) as a surrogate for a

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-10 Thread Jason Wang
On Thu, 2014-04-10 at 21:42 -0400, Steven Galgano wrote: > On 04/10/2014 06:29 AM, Michael S. Tsirkin wrote: > > On Wed, Apr 09, 2014 at 10:19:40PM -0400, Steven Galgano wrote: > >> Add tuntap flow control support for use by back pressure routing > >> protocols. Setting the new TUNSETIFF flag

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-10 Thread Jason Wang
On Thu, 2014-04-10 at 13:29 +0300, Michael S. Tsirkin wrote: > On Wed, Apr 09, 2014 at 10:19:40PM -0400, Steven Galgano wrote: > > Add tuntap flow control support for use by back pressure routing protocols. > > Setting the new TUNSETIFF flag IFF_FLOW_CONTROL, will signal resources as > >

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-10 Thread Steven Galgano
On 04/10/2014 06:29 AM, Michael S. Tsirkin wrote: > On Wed, Apr 09, 2014 at 10:19:40PM -0400, Steven Galgano wrote: >> Add tuntap flow control support for use by back pressure routing protocols. >> Setting the new TUNSETIFF flag IFF_FLOW_CONTROL, will signal resources as >> unavailable when the

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-10 Thread Steven Galgano
On 04/10/2014 06:29 AM, Michael S. Tsirkin wrote: On Wed, Apr 09, 2014 at 10:19:40PM -0400, Steven Galgano wrote: Add tuntap flow control support for use by back pressure routing protocols. Setting the new TUNSETIFF flag IFF_FLOW_CONTROL, will signal resources as unavailable when the tx

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-10 Thread Jason Wang
On Thu, 2014-04-10 at 13:29 +0300, Michael S. Tsirkin wrote: On Wed, Apr 09, 2014 at 10:19:40PM -0400, Steven Galgano wrote: Add tuntap flow control support for use by back pressure routing protocols. Setting the new TUNSETIFF flag IFF_FLOW_CONTROL, will signal resources as unavailable

Re: [PATCH] tuntap: add flow control to support back pressure

2014-04-10 Thread Jason Wang
On Thu, 2014-04-10 at 21:42 -0400, Steven Galgano wrote: On 04/10/2014 06:29 AM, Michael S. Tsirkin wrote: On Wed, Apr 09, 2014 at 10:19:40PM -0400, Steven Galgano wrote: Add tuntap flow control support for use by back pressure routing protocols. Setting the new TUNSETIFF flag

[PATCH] tuntap: add flow control to support back pressure

2014-04-09 Thread Steven Galgano
Add tuntap flow control support for use by back pressure routing protocols. Setting the new TUNSETIFF flag IFF_FLOW_CONTROL, will signal resources as unavailable when the tx queue limit is reached by issuing a netif_tx_stop_all_queues() rather than discarding frames. A

[PATCH] tuntap: add flow control to support back pressure

2014-04-09 Thread Steven Galgano
Add tuntap flow control support for use by back pressure routing protocols. Setting the new TUNSETIFF flag IFF_FLOW_CONTROL, will signal resources as unavailable when the tx queue limit is reached by issuing a netif_tx_stop_all_queues() rather than discarding frames. A