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author | John Fastabend <john.r.fastabend@intel.com> | 2010-10-28 00:59:57 +0000 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2010-10-28 10:19:00 -0700 |
commit | 9806307a1c5a2a79e268ae4e78b437d38c8adf7f (patch) | |
tree | 1a4ceada09e85a3cd9083790c6b16a16e99bb928 /drivers/net/ixgbe/ixgbe_dcb.c | |
parent | affa9dfb04b7e2e3a0b0e6d844ea0c9ed97505f9 (diff) | |
download | op-kernel-dev-9806307a1c5a2a79e268ae4e78b437d38c8adf7f.zip op-kernel-dev-9806307a1c5a2a79e268ae4e78b437d38c8adf7f.tar.gz |
ixgbe: DCB, fix TX hang occurring in stress condition with PFC
The DCB credits refill quantum _must_ be greater than half the max
packet size. This is needed to guarantee that TX DMA operations
are not attempted during a pause state. Additionally, the min IFG
must be set correctly for DCB mode. If a DMA operation is
requested unexpectedly during the pause state the HW data
store may be corrupted leading to a DMA hang. The DMA hang
requires a reset to correct. This fixes the HW configuration
to avoid this condition.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ixgbe/ixgbe_dcb.c')
-rw-r--r-- | drivers/net/ixgbe/ixgbe_dcb.c | 39 |
1 files changed, 34 insertions, 5 deletions
diff --git a/drivers/net/ixgbe/ixgbe_dcb.c b/drivers/net/ixgbe/ixgbe_dcb.c index 8bb9ddb..0d44c64 100644 --- a/drivers/net/ixgbe/ixgbe_dcb.c +++ b/drivers/net/ixgbe/ixgbe_dcb.c @@ -43,9 +43,12 @@ * ixgbe_dcb_check_config(). */ s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *dcb_config, - u8 direction) + int max_frame, u8 direction) { struct tc_bw_alloc *p; + int min_credit; + int min_multiplier; + int min_percent = 100; s32 ret_val = 0; /* Initialization values default for Tx settings */ u32 credit_refill = 0; @@ -59,6 +62,31 @@ s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *dcb_config, goto out; } + min_credit = ((max_frame / 2) + DCB_CREDIT_QUANTUM - 1) / + DCB_CREDIT_QUANTUM; + + /* Find smallest link percentage */ + for (i = 0; i < MAX_TRAFFIC_CLASS; i++) { + p = &dcb_config->tc_config[i].path[direction]; + bw_percent = dcb_config->bw_percentage[direction][p->bwg_id]; + link_percentage = p->bwg_percent; + + link_percentage = (link_percentage * bw_percent) / 100; + + if (link_percentage && link_percentage < min_percent) + min_percent = link_percentage; + } + + /* + * The ratio between traffic classes will control the bandwidth + * percentages seen on the wire. To calculate this ratio we use + * a multiplier. It is required that the refill credits must be + * larger than the max frame size so here we find the smallest + * multiplier that will allow all bandwidth percentages to be + * greater than the max frame size. + */ + min_multiplier = (min_credit / min_percent) + 1; + /* Find out the link percentage for each TC first */ for (i = 0; i < MAX_TRAFFIC_CLASS; i++) { p = &dcb_config->tc_config[i].path[direction]; @@ -73,8 +101,9 @@ s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *dcb_config, /* Save link_percentage for reference */ p->link_percent = (u8)link_percentage; - /* Calculate credit refill and save it */ - credit_refill = link_percentage * MINIMUM_CREDIT_REFILL; + /* Calculate credit refill ratio using multiplier */ + credit_refill = min(link_percentage * min_multiplier, + MAX_CREDIT_REFILL); p->data_credits_refill = (u16)credit_refill; /* Calculate maximum credit for the TC */ @@ -85,8 +114,8 @@ s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *dcb_config, * of a TC is too small, the maximum credit may not be * enough to send out a jumbo frame in data plane arbitration. */ - if (credit_max && (credit_max < MINIMUM_CREDIT_FOR_JUMBO)) - credit_max = MINIMUM_CREDIT_FOR_JUMBO; + if (credit_max && (credit_max < min_credit)) + credit_max = min_credit; if (direction == DCB_TX_CONFIG) { /* |