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e1000e: Fix default interrupt throttle rate not set in NIC HW

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Based on the original patch from  Ying Cai <ycai@google.com>
This change ensures that the itr/itr_setting adjustment logic is used,
even for the default/compiled-in value.

Context:
  When we changed the default InterruptThrottleRate value from default
  (3 = dynamic mode) to 8000 for example, only adapter->itr_setting
  (which controls interrupt coalescing mode) was set to 8000, but
  adapter->itr (which controls the value set in NIC register) was not
  updated accordingly. So from ethtool, it seemed the interrupt
  throttling is enabled at 8000 intr/s, but the NIC actually was
  running in dynamic mode which has lower CPU efficiency especially
  when throughput is not high.

CC: Ying Cai <ycai@google.com>
CC: David Decotigny <david.decotigny@google.com>
Signed-off-by: Jeff Kirsher <jeffrey.kirsher@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
This commit is contained in:
Jeff Kirsher 2012-04-20 08:51:45 +00:00
parent 569a3aff70
commit 727c356f4d
1 changed files with 53 additions and 46 deletions
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99
drivers/net/ethernet/intel/e1000e/param.c
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@ -106,7 +106,7 @@ E1000_PARAM(RxAbsIntDelay, "Receive Absolute Interrupt Delay");
/*
* Interrupt Throttle Rate (interrupts/sec)
*
* Valid Range: 100-100000 (0=off, 1=dynamic, 3=dynamic conservative)
* Valid Range: 100-100000 or one of: 0=off, 1=dynamic, 3=dynamic conservative
*/
E1000_PARAM(InterruptThrottleRate, "Interrupt Throttling Rate");
#define DEFAULT_ITR 3
@ -344,53 +344,60 @@ void __devinit e1000e_check_options(struct e1000_adapter *adapter)
if (num_InterruptThrottleRate > bd) {
adapter->itr = InterruptThrottleRate[bd];
switch (adapter->itr) {
case 0:
e_info("%s turned off\n", opt.name);
break;
case 1:
e_info("%s set to dynamic mode\n", opt.name);
adapter->itr_setting = adapter->itr;
adapter->itr = 20000;
break;
case 3:
e_info("%s set to dynamic conservative mode\n",
opt.name);
adapter->itr_setting = adapter->itr;
adapter->itr = 20000;
break;
case 4:
e_info("%s set to simplified (2000-8000 ints) "
"mode\n", opt.name);
adapter->itr_setting = 4;
break;
default:
/*
* Save the setting, because the dynamic bits
* change itr.
*/
if (e1000_validate_option(&adapter->itr, &opt,
adapter) &&
(adapter->itr == 3)) {
/*
* In case of invalid user value,
* default to conservative mode.
*/
adapter->itr_setting = adapter->itr;
adapter->itr = 20000;
} else {
/*
* Clear the lower two bits because
* they are used as control.
*/
adapter->itr_setting =
adapter->itr & ~3;
}
break;
}
/*
* Make sure a message is printed for non-special
* values. And in case of an invalid option, display
* warning, use default and got through itr/itr_setting
* adjustment logic below
*/
if ((adapter->itr > 4) &&
e1000_validate_option(&adapter->itr, &opt, adapter))
adapter->itr = opt.def;
} else {
adapter->itr_setting = opt.def;
/*
* If no option specified, use default value and go
* through the logic below to adjust itr/itr_setting
*/
adapter->itr = opt.def;
/*
* Make sure a message is printed for non-special
* default values
*/
if (adapter->itr > 40)
e_info("%s set to default %d\n", opt.name,
adapter->itr);
}
adapter->itr_setting = adapter->itr;
switch (adapter->itr) {
case 0:
e_info("%s turned off\n", opt.name);
break;
case 1:
e_info("%s set to dynamic mode\n", opt.name);
adapter->itr = 20000;
break;
case 3:
e_info("%s set to dynamic conservative mode\n",
opt.name);
adapter->itr = 20000;
break;
case 4:
e_info("%s set to simplified (2000-8000 ints) mode\n",
opt.name);
break;
default:
/*
* Save the setting, because the dynamic bits
* change itr.
*
* Clear the lower two bits because
* they are used as control.
*/
adapter->itr_setting &= ~3;
break;
}
}
{ /* Interrupt Mode */