[RFC] app/testpmd: fix MTU after device configure
diff mbox series

Message ID 20201105180942.2938152-1-ferruh.yigit@intel.com
State Superseded, archived
Delegated to: Ferruh Yigit
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  • [RFC] app/testpmd: fix MTU after device configure
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Context Check Description
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Ferruh Yigit Nov. 5, 2020, 6:09 p.m. UTC
In 'rte_eth_dev_configure()', if 'DEV_RX_OFFLOAD_JUMBO_FRAME' is not set
the max frame size is limited to 'RTE_ETHER_MAX_LEN' (1518).
This is mistake because for the PMDs that has frame size bigger than
"RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN" (18 bytes), the MTU becomes
less than 1500, causing a valid frame with 1500 bytes payload to be
dropped.

Since 'rte_eth_dev_set_mtu()' works as expected, it is called after
'rte_eth_dev_configure()' to fix the MTU.
It may look redundant to set MTU after 'rte_eth_dev_configure()', both
with default values, but it is not, the resulting MTU config can be
different in the device based on frame overhead of the PMD.

And instead of setting the MTU to default value, it is first get via
'rte_eth_dev_get_mtu()' and set again, this is to cover cases MTU
changed from testpmd command line.

'rte_eth_dev_set_mtu()', '-ENOTSUP' error is ignored to prevent
irrelevant warning messages for the virtual PMDs.

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
Cc: Steve Yang <stevex.yang@intel.com>
Cc: Thomas Monjalon <thomas@monjalon.net>
Cc: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Cc: Konstantin Ananyev <konstantin.ananyev@intel.com>
Cc: Olivier Matz <olivier.matz@6wind.com>
Cc: Lance Richardson <lance.richardson@broadcom.com>
---
 app/test-pmd/testpmd.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

Comments

Ferruh Yigit Nov. 11, 2020, 12:58 p.m. UTC | #1
On 11/5/2020 6:09 PM, Ferruh Yigit wrote:
> In 'rte_eth_dev_configure()', if 'DEV_RX_OFFLOAD_JUMBO_FRAME' is not set
> the max frame size is limited to 'RTE_ETHER_MAX_LEN' (1518).
> This is mistake because for the PMDs that has frame size bigger than
> "RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN" (18 bytes), the MTU becomes
> less than 1500, causing a valid frame with 1500 bytes payload to be
> dropped.
> 
> Since 'rte_eth_dev_set_mtu()' works as expected, it is called after
> 'rte_eth_dev_configure()' to fix the MTU.
> It may look redundant to set MTU after 'rte_eth_dev_configure()', both
> with default values, but it is not, the resulting MTU config can be
> different in the device based on frame overhead of the PMD.
> 
> And instead of setting the MTU to default value, it is first get via
> 'rte_eth_dev_get_mtu()' and set again, this is to cover cases MTU
> changed from testpmd command line.
> 
> 'rte_eth_dev_set_mtu()', '-ENOTSUP' error is ignored to prevent
> irrelevant warning messages for the virtual PMDs.
> 
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
> Cc: Steve Yang <stevex.yang@intel.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>
> Cc: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> Cc: Konstantin Ananyev <konstantin.ananyev@intel.com>
> Cc: Olivier Matz <olivier.matz@6wind.com>
> Cc: Lance Richardson <lance.richardson@broadcom.com>
> ---
>   app/test-pmd/testpmd.c | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)
> 
> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
> index 33fc0fddf5..48e9647fc7 100644
> --- a/app/test-pmd/testpmd.c
> +++ b/app/test-pmd/testpmd.c
> @@ -2537,6 +2537,8 @@ start_port(portid_t pid)
>   		}
>   
>   		if (port->need_reconfig > 0) {
> +			uint16_t mtu = RTE_ETHER_MTU;
> +
>   			port->need_reconfig = 0;
>   
>   			if (flow_isolate_all) {
> @@ -2570,6 +2572,23 @@ start_port(portid_t pid)
>   				port->need_reconfig = 1;
>   				return -1;
>   			}
> +
> +			/*
> +			 * Workaround for rte_eth_dev_configure(), max_rx_pkt_len
> +			 * set MTU wrong for the PMDs that have frame overhead
> +			 * bigger than RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN.
> +			 * For a PMD that has 26 bytes overhead, rte_eth_dev_configure()
> +			 * can set MTU to max 1492, not to expected 1500 bytes.
> +			 * Using rte_eth_dev_set_mtu() to be able to set MTU correctly,
> +			 * default MTU value is 1500.
> +			 */
> +			diag = rte_eth_dev_get_mtu(pi, &mtu);
> +			if (diag)
> +				printf("Failed to get MTU for port %d\n", pi);
> +			diag = rte_eth_dev_set_mtu(pi, mtu);
> +			if (diag != 0 && diag != -ENOTSUP)
> +				printf("Failed to set MTU to %u for port %d\n",
> +						mtu, pi);
>   		}
>   		if (port->need_reconfig_queues > 0) {
>   			port->need_reconfig_queues = 0;
> 

Hi Steve,

Since your patch [1] for the fix reverted [2], can you please test above patch? 
If it works as expected I will send as actual patch.

Thanks,
ferruh

[1]
https://git.dpdk.org/dpdk/commit/?id=f6870a7ed6b3

[2]
https://git.dpdk.org/dpdk/commit/?id=13e0b599acfd
Zhang, Qi Z Nov. 13, 2020, 10:37 a.m. UTC | #2
> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Ferruh Yigit
> Sent: Friday, November 6, 2020 2:10 AM
> To: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Xing, Beilei
> <beilei.xing@intel.com>; Iremonger, Bernard <bernard.iremonger@intel.com>
> Cc: Yigit, Ferruh <ferruh.yigit@intel.com>; dev@dpdk.org; Yang, SteveX
> <stevex.yang@intel.com>; Thomas Monjalon <thomas@monjalon.net>;
> Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>; Ananyev, Konstantin
> <konstantin.ananyev@intel.com>; Olivier Matz <olivier.matz@6wind.com>;
> Lance Richardson <lance.richardson@broadcom.com>
> Subject: [dpdk-dev] [RFC] app/testpmd: fix MTU after device configure
> 
> In 'rte_eth_dev_configure()', if 'DEV_RX_OFFLOAD_JUMBO_FRAME' is not set
> the max frame size is limited to 'RTE_ETHER_MAX_LEN' (1518).
> This is mistake because for the PMDs that has frame size bigger than
> "RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN" (18 bytes), the MTU becomes
> less than 1500, causing a valid frame with 1500 bytes payload to be dropped.
> 
> Since 'rte_eth_dev_set_mtu()' works as expected, it is called after
> 'rte_eth_dev_configure()' to fix the MTU.
> It may look redundant to set MTU after 'rte_eth_dev_configure()', both with
> default values, but it is not, the resulting MTU config can be different in the
> device based on frame overhead of the PMD.
> 
> And instead of setting the MTU to default value, it is first get via
> 'rte_eth_dev_get_mtu()' and set again, this is to cover cases MTU changed
> from testpmd command line.
> 
> 'rte_eth_dev_set_mtu()', '-ENOTSUP' error is ignored to prevent irrelevant
> warning messages for the virtual PMDs.
> 
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>

Reviewed-by: Qi Zhang <qi.z.zhang@intel.com>

> ---
> Cc: Steve Yang <stevex.yang@intel.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>
> Cc: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> Cc: Konstantin Ananyev <konstantin.ananyev@intel.com>
> Cc: Olivier Matz <olivier.matz@6wind.com>
> Cc: Lance Richardson <lance.richardson@broadcom.com>
> ---
>  app/test-pmd/testpmd.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c index
> 33fc0fddf5..48e9647fc7 100644
> --- a/app/test-pmd/testpmd.c
> +++ b/app/test-pmd/testpmd.c
> @@ -2537,6 +2537,8 @@ start_port(portid_t pid)
>  		}
> 
>  		if (port->need_reconfig > 0) {
> +			uint16_t mtu = RTE_ETHER_MTU;
> +
>  			port->need_reconfig = 0;
> 
>  			if (flow_isolate_all) {
> @@ -2570,6 +2572,23 @@ start_port(portid_t pid)
>  				port->need_reconfig = 1;
>  				return -1;
>  			}
> +
> +			/*
> +			 * Workaround for rte_eth_dev_configure(), max_rx_pkt_len
> +			 * set MTU wrong for the PMDs that have frame overhead
> +			 * bigger than RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN.
> +			 * For a PMD that has 26 bytes overhead,
> rte_eth_dev_configure()
> +			 * can set MTU to max 1492, not to expected 1500 bytes.
> +			 * Using rte_eth_dev_set_mtu() to be able to set MTU
> correctly,
> +			 * default MTU value is 1500.
> +			 */
> +			diag = rte_eth_dev_get_mtu(pi, &mtu);
> +			if (diag)
> +				printf("Failed to get MTU for port %d\n", pi);
> +			diag = rte_eth_dev_set_mtu(pi, mtu);
> +			if (diag != 0 && diag != -ENOTSUP)
> +				printf("Failed to set MTU to %u for port %d\n",
> +						mtu, pi);
>  		}
>  		if (port->need_reconfig_queues > 0) {
>  			port->need_reconfig_queues = 0;
> --
> 2.26.2

Patch
diff mbox series

diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 33fc0fddf5..48e9647fc7 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -2537,6 +2537,8 @@  start_port(portid_t pid)
 		}
 
 		if (port->need_reconfig > 0) {
+			uint16_t mtu = RTE_ETHER_MTU;
+
 			port->need_reconfig = 0;
 
 			if (flow_isolate_all) {
@@ -2570,6 +2572,23 @@  start_port(portid_t pid)
 				port->need_reconfig = 1;
 				return -1;
 			}
+
+			/*
+			 * Workaround for rte_eth_dev_configure(), max_rx_pkt_len
+			 * set MTU wrong for the PMDs that have frame overhead
+			 * bigger than RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN.
+			 * For a PMD that has 26 bytes overhead, rte_eth_dev_configure()
+			 * can set MTU to max 1492, not to expected 1500 bytes.
+			 * Using rte_eth_dev_set_mtu() to be able to set MTU correctly,
+			 * default MTU value is 1500.
+			 */
+			diag = rte_eth_dev_get_mtu(pi, &mtu);
+			if (diag)
+				printf("Failed to get MTU for port %d\n", pi);
+			diag = rte_eth_dev_set_mtu(pi, mtu);
+			if (diag != 0 && diag != -ENOTSUP)
+				printf("Failed to set MTU to %u for port %d\n",
+						mtu, pi);
 		}
 		if (port->need_reconfig_queues > 0) {
 			port->need_reconfig_queues = 0;