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i40e/i40evf: fix bug in throttle rate math

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The driver was using a value expressed in 2us increments
for the divisor to figure out our bytes/usec values.

Fix the usecs variable to contain a value in microseconds.

Change-ID: I5c20493103c295d6f201947bb908add7040b7c41
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Jesse Brandeburg 2015-09-28 14:16:52 -04:00 • committed by Jeff Kirsher
parent 8f5e39ce92
commit 51cc6d9fcc
2 changed files with 16 additions and 2 deletions
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9
drivers/net/ethernet/intel/i40e/i40e_txrx.c
View file

@ -830,6 +830,7 @@ static bool i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
enum i40e_latency_range new_latency_range = rc->latency_range; enum i40e_latency_range new_latency_range = rc->latency_range;
u32 new_itr = rc->itr; u32 new_itr = rc->itr;
int bytes_per_int; int bytes_per_int;
int usecs;
if (rc->total_packets == 0 || !rc->itr) if (rc->total_packets == 0 || !rc->itr)
return false; return false;
@ -838,8 +839,14 @@ static bool i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
* 0-10MB/s lowest (100000 ints/s) * 0-10MB/s lowest (100000 ints/s)
* 10-20MB/s low (20000 ints/s) * 10-20MB/s low (20000 ints/s)
* 20-1249MB/s bulk (8000 ints/s) * 20-1249MB/s bulk (8000 ints/s)
*
* The math works out because the divisor is in 10^(-6) which
* turns the bytes/us input value into MB/s values, but
* make sure to use usecs, as the register values written
* are in 2 usec increments in the ITR registers.
*/ */
bytes_per_int = rc->total_bytes / rc->itr; usecs = (rc->itr << 1);
bytes_per_int = rc->total_bytes / usecs;
switch (new_latency_range) { switch (new_latency_range) {
case I40E_LOWEST_LATENCY: case I40E_LOWEST_LATENCY:
if (bytes_per_int > 10) if (bytes_per_int > 10)

9
drivers/net/ethernet/intel/i40evf/i40e_txrx.c
View file

@ -333,6 +333,7 @@ static bool i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
enum i40e_latency_range new_latency_range = rc->latency_range; enum i40e_latency_range new_latency_range = rc->latency_range;
u32 new_itr = rc->itr; u32 new_itr = rc->itr;
int bytes_per_int; int bytes_per_int;
int usecs;
if (rc->total_packets == 0 || !rc->itr) if (rc->total_packets == 0 || !rc->itr)
return false; return false;
@ -341,8 +342,14 @@ static bool i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
* 0-10MB/s lowest (100000 ints/s) * 0-10MB/s lowest (100000 ints/s)
* 10-20MB/s low (20000 ints/s) * 10-20MB/s low (20000 ints/s)
* 20-1249MB/s bulk (8000 ints/s) * 20-1249MB/s bulk (8000 ints/s)
*
* The math works out because the divisor is in 10^(-6) which
* turns the bytes/us input value into MB/s values, but
* make sure to use usecs, as the register values written
* are in 2 usec increments in the ITR registers.
*/ */
bytes_per_int = rc->total_bytes / rc->itr; usecs = (rc->itr << 1);
bytes_per_int = rc->total_bytes / usecs;
switch (new_latency_range) { switch (new_latency_range) {
case I40E_LOWEST_LATENCY: case I40E_LOWEST_LATENCY:
if (bytes_per_int > 10) if (bytes_per_int > 10)