netdev - [PATCH v2 net] ibmveth: Reduce maximum tx queues to 8

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Date:   Wed,  2 Nov 2022 13:38:37 -0500
From:   Nick Child <nnac123@...ux.ibm.com>
To:     netdev@...r.kernel.org
Cc:     nick.child@....com, bjking1@...ux.ibm.com, ricklind@...ibm.com,
        dave.taht@...il.com, Nick Child <nnac123@...ux.ibm.com>
Subject: [PATCH v2 net] ibmveth: Reduce maximum tx queues to 8

Previously, the maximum number of transmit queues allowed was 16. Due to
resource concerns, limit to 8 queues instead.

Since the driver is virtualized away from the physical NIC, the purpose
of multiple queues is purely to allow for parallel calls to the
hypervisor. Therefore, there is no noticeable effect on performance by
reducing queue count to 8.

Reported-by: Dave Taht <dave.taht@...il.com>
Signed-off-by: Nick Child <nnac123@...ux.ibm.com>
---
Relevant links:
 - Introduce multiple tx queues (accepted in v6.1):
   https://lore.kernel.org/netdev/20220928214350.29795-2-nnac123@linux.ibm.com/
 - Resource concerns with 16 queues:
   https://lore.kernel.org/netdev/CAA93jw5reJmaOvt9vw15C1fo1AN7q5jVKzUocbAoNDC-cpi=KQ@mail.gmail.com/
  - v1 (only change is commit message length and typo in Reported-by tag):
    https://lore.kernel.org/netdev/20221102153040.149244-1-nnac123@linux.ibm.com/
 drivers/net/ethernet/ibm/ibmveth.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ibm/ibmveth.h b/drivers/net/ethernet/ibm/ibmveth.h
index 4f8357187292..6b5faf1feb0b 100644
--- a/drivers/net/ethernet/ibm/ibmveth.h
+++ b/drivers/net/ethernet/ibm/ibmveth.h
@@ -99,7 +99,7 @@ static inline long h_illan_attributes(unsigned long unit_address,
 #define IBMVETH_FILT_LIST_SIZE 4096
 #define IBMVETH_MAX_BUF_SIZE (1024 * 128)
 #define IBMVETH_MAX_TX_BUF_SIZE (1024 * 64)
-#define IBMVETH_MAX_QUEUES 16U
+#define IBMVETH_MAX_QUEUES 8U
 
 static int pool_size[] = { 512, 1024 * 2, 1024 * 16, 1024 * 32, 1024 * 64 };
 static int pool_count[] = { 256, 512, 256, 256, 256 };
-- 
2.31.1