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* [Intel-wired-lan] [PATCH 249/249] net:ethernet:intel:igb_main.c: Add Throttling disable option in order to decrease latency usually required by RT applications.
@ 2016-09-06 13:17 Amir Yihie
  2016-09-06 14:00   ` [Intel-wired-lan] " Steven Rostedt
  2016-09-06 14:46 ` Amir Yihie
  0 siblings, 2 replies; 6+ messages in thread
From: Amir Yihie @ 2016-09-06 13:17 UTC (permalink / raw)
  To: intel-wired-lan


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^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 249/249] net:ethernet:intel:igb_main.c: Add Throttling disable option in order to decrease latency usually required by RT applications.
  2016-09-06 13:17 [Intel-wired-lan] [PATCH 249/249] net:ethernet:intel:igb_main.c: Add Throttling disable option in order to decrease latency usually required by RT applications Amir Yihie
@ 2016-09-06 14:00   ` Steven Rostedt
  2016-09-06 14:46 ` Amir Yihie
  1 sibling, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2016-09-06 14:00 UTC (permalink / raw)
  To: Amir Yihie
  Cc: jeffrey.t.kirsher, jesse.brandeburg, shannon.nelson,
	carolyn.wyborny, donald.c.skidmore, matthew.vick, john.ronciak,
	mitch.a.williams, intel-wired-lan, netdev, linux-kernel

On Tue, 6 Sep 2016 13:17:04 +0000
Amir Yihie <amiry@waves.com> wrote:

> 

I guess there's not much to do here?

-- Steve

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Intel-wired-lan] [PATCH 249/249] net:ethernet:intel:igb_main.c: Add Throttling disable option in order to decrease latency usually required by RT applications.
@ 2016-09-06 14:00   ` Steven Rostedt
  0 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2016-09-06 14:00 UTC (permalink / raw)
  To: intel-wired-lan

On Tue, 6 Sep 2016 13:17:04 +0000
Amir Yihie <amiry@waves.com> wrote:

> 

I guess there's not much to do here?

-- Steve

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Intel-wired-lan] [PATCH 249/249] net:ethernet:intel:igb_main.c: Add Throttling disable option in order to decrease latency usually required by RT applications.
  2016-09-06 13:17 [Intel-wired-lan] [PATCH 249/249] net:ethernet:intel:igb_main.c: Add Throttling disable option in order to decrease latency usually required by RT applications Amir Yihie
  2016-09-06 14:00   ` [Intel-wired-lan] " Steven Rostedt
@ 2016-09-06 14:46 ` Amir Yihie
  2016-09-07 14:49     ` Duyck, Alexander H
  1 sibling, 1 reply; 6+ messages in thread
From: Amir Yihie @ 2016-09-06 14:46 UTC (permalink / raw)
  To: intel-wired-lan


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^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [Intel-wired-lan] [PATCH 249/249] net:ethernet:intel:igb_main.c: Add Throttling disable option in order to decrease latency usually required by RT applications.
  2016-09-06 14:46 ` Amir Yihie
@ 2016-09-07 14:49     ` Duyck, Alexander H
  0 siblings, 0 replies; 6+ messages in thread
From: Duyck, Alexander H @ 2016-09-07 14:49 UTC (permalink / raw)
  To: amiry, Kirsher, Jeffrey T
  Cc: linux-kernel, netdev, intel-wired-lan, shannon.nelson, rostedt,
	matthew.vick, john.ronciak

On Tue, 2016-09-06 at 14:46 +0000, Amir Yihie wrote:
> From e433f5bedd49a65b7337d025f3f204f0f21ad5e5 Mon Sep 17 00:00:00
> 2001
> From: amiry <amiry@waves.com>
> Date: Tue, 6 Sep 2016 14:58:38 +0300
> Subject: [PATCH 249/249] net:ethernet:intel:igb_main.c: Add
> Throttling disable
>  option in order to decrease latency usually required by RT
> applications.
> 
> Add an option to Disable Throttling algorithm , which will result
> with minimum latency on received frames .
> mainly targets for RT application that look for low larceny and less
> cares about throughput .
> How to use :
> On insmod , add parameter : InterruptThrottleRate=0
> 
> This patch is currently against a linux 4.1.27-rt31 kernel.
> 
> Signed-off-by: Amir Yihie <amiry@waves.com>
> ---
>  drivers/net/ethernet/intel/igb/igb_main.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c
> b/drivers/net/ethernet/intel/igb/igb_main.c
> index 7dfbcde..9480850 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -251,6 +251,14 @@ static int debug = -1;
>  module_param(debug, int, 0);
>  MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");
>  
> +/* Interrupt Throttle Rate (interrupts/sec)
> + *
> + * Valid Range: 0=off, 3=dynamic conservative
> + */
> +static int InterruptThrottleRate = 3;
> +module_param(InterruptThrottleRate, int, 0);
> +MODULE_PARM_DESC(InterruptThrottleRate, "InterruptThrottleRate
> (0=off, 3=dynamic conservative)");
> +

This is creating redundant functionality.  The same can be done via the
ethtool command "ethtool -C <iface> rx-usecs 0".  Is there some reason
why you couldn't use ethtool?

>  struct igb_reg_info {
>         u32 ofs;
>         char *name;
> @@ -2966,6 +2974,9 @@ static int igb_sw_init(struct igb_adapter
> *adapter)
>         adapter->rx_itr_setting = IGB_DEFAULT_ITR;
>         adapter->tx_itr_setting = IGB_DEFAULT_ITR;
>  
> +       if (InterruptThrottleRate == 0)
> +               adapter->rx_itr_setting = InterruptThrottleRate;
> +
>         /* set default work limits */
>         adapter->tx_work_limit = IGB_DEFAULT_TX_WORK;

If you are going to use InterruptThrottleRate you might as well use it
fully instead of making it a boolean value with 0 having one meaning
and the default of 3 being another.

Thanks.

- Alex

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Intel-wired-lan] [PATCH 249/249] net:ethernet:intel:igb_main.c: Add Throttling disable option in order to decrease latency usually required by RT applications.
@ 2016-09-07 14:49     ` Duyck, Alexander H
  0 siblings, 0 replies; 6+ messages in thread
From: Duyck, Alexander H @ 2016-09-07 14:49 UTC (permalink / raw)
  To: intel-wired-lan

On Tue, 2016-09-06 at 14:46 +0000, Amir Yihie wrote:
> From e433f5bedd49a65b7337d025f3f204f0f21ad5e5 Mon Sep 17 00:00:00
> 2001
> From: amiry <amiry@waves.com>
> Date: Tue, 6 Sep 2016 14:58:38 +0300
> Subject: [PATCH 249/249] net:ethernet:intel:igb_main.c: Add
> Throttling disable
> ?option in order to decrease latency usually required by RT
> applications.
> 
> Add an option to Disable Throttling algorithm , which will result
> with minimum latency on received frames .
> mainly targets for RT application that look for low larceny and less
> cares about throughput .
> How to use :
> On insmod , add parameter : InterruptThrottleRate=0
> 
> This patch is currently against a linux 4.1.27-rt31 kernel.
> 
> Signed-off-by: Amir Yihie <amiry@waves.com>
> ---
> ?drivers/net/ethernet/intel/igb/igb_main.c | 11 +++++++++++
> ?1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c
> b/drivers/net/ethernet/intel/igb/igb_main.c
> index 7dfbcde..9480850 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -251,6 +251,14 @@ static int debug = -1;
> ?module_param(debug, int, 0);
> ?MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");
> ?
> +/* Interrupt Throttle Rate (interrupts/sec)
> + *
> + * Valid Range: 0=off, 3=dynamic conservative
> + */
> +static int InterruptThrottleRate = 3;
> +module_param(InterruptThrottleRate, int, 0);
> +MODULE_PARM_DESC(InterruptThrottleRate, "InterruptThrottleRate
> (0=off, 3=dynamic conservative)");
> +

This is creating redundant functionality. ?The same can be done via the
ethtool command "ethtool -C <iface> rx-usecs 0". ?Is there some reason
why you couldn't use ethtool?

> ?struct igb_reg_info {
> ????????u32 ofs;
> ????????char *name;
> @@ -2966,6 +2974,9 @@ static int igb_sw_init(struct igb_adapter
> *adapter)
> ????????adapter->rx_itr_setting = IGB_DEFAULT_ITR;
> ????????adapter->tx_itr_setting = IGB_DEFAULT_ITR;
> ?
> +???????if (InterruptThrottleRate == 0)
> +???????????????adapter->rx_itr_setting = InterruptThrottleRate;
> +
> ????????/* set default work limits */
> ????????adapter->tx_work_limit = IGB_DEFAULT_TX_WORK;

If you are going to use InterruptThrottleRate you might as well use it
fully instead of making it a boolean value with 0 having one meaning
and the default of 3 being another.

Thanks.

- Alex

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2016-09-07 14:52 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-09-06 13:17 [Intel-wired-lan] [PATCH 249/249] net:ethernet:intel:igb_main.c: Add Throttling disable option in order to decrease latency usually required by RT applications Amir Yihie
2016-09-06 14:00 ` Steven Rostedt
2016-09-06 14:00   ` [Intel-wired-lan] " Steven Rostedt
2016-09-06 14:46 ` Amir Yihie
2016-09-07 14:49   ` Duyck, Alexander H
2016-09-07 14:49     ` Duyck, Alexander H

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