Thread (37 messages) 37 messages, 7 authors, 2021-01-29

Re: [dpdk-dev] [PATCH v5] app/testpmd: fix setting maximum packet length

From: Lance Richardson <hidden>
Date: 2021-01-26 03:22:34

Acked-by: Lance Richardson <redacted>

Thanks,
    Lance

On Mon, Jan 25, 2021 at 7:44 PM Ferruh Yigit [off-list ref] wrote:
On 1/25/2021 7:41 PM, Lance Richardson wrote:
quoted
On Mon, Jan 25, 2021 at 1:15 PM Ferruh Yigit [off-list ref] wrote:
quoted
From: Steve Yang <redacted>

"port config all max-pkt-len" command fails because it doesn't set the
'DEV_RX_OFFLOAD_JUMBO_FRAME' offload flag properly.

Commit in the fixes line moved the 'DEV_RX_OFFLOAD_JUMBO_FRAME' offload
flag update from 'cmd_config_max_pkt_len_parsed()' to 'init_config()'.
'init_config()' function is only called during testpmd startup, but the
flag status needs to be calculated whenever 'max_rx_pkt_len' changes.

The issue can be reproduce as [1], where the 'max-pkt-len' reduced and
'DEV_RX_OFFLOAD_JUMBO_FRAME' offload flag should be cleared but it
didn't.

Adding the 'update_jumbo_frame_offload()' helper function to update
'DEV_RX_OFFLOAD_JUMBO_FRAME' offload flag and 'max_rx_pkt_len'. This
function is called both by 'init_config()' and
'cmd_config_max_pkt_len_parsed()'.

Default 'max-pkt-len' value set to zero, 'update_jumbo_frame_offload()'
updates it to "RTE_ETHER_MTU + PMD specific Ethernet overhead" when it
is zero.
If '--max-pkt-len=N' argument provided, it will be used instead.
And with each "port config all max-pkt-len" command, the
'DEV_RX_OFFLOAD_JUMBO_FRAME' offload flag, 'max-pkt-len' and MTU is
updated.

[1]
<snip>
quoted
+/*
+ * Helper function to arrange max_rx_pktlen value and JUMBO_FRAME offload,
+ * MTU is also aligned if JUMBO_FRAME offload is not set.
+ *
+ * port->dev_info should be get before calling this function.
Should this be "port->dev_info should be set ..." instead?
Ack.
quoted
<snip>
quoted
+       if (rx_offloads != port->dev_conf.rxmode.offloads) {
+               uint16_t qid;
+
+               port->dev_conf.rxmode.offloads = rx_offloads;
+
+               /* Apply JUMBO_FRAME offload configuration to Rx queue(s) */
+               for (qid = 0; qid < port->dev_info.nb_rx_queues; qid++) {
+                       if (on)
+                               port->rx_conf[qid].offloads |= DEV_RX_OFFLOAD_JUMBO_FRAME;
+                       else
+                               port->rx_conf[qid].offloads &= ~DEV_RX_OFFLOAD_JUMBO_FRAME;
+               }
Is it correct to set per-queue offloads that aren't advertised by the PMD
as supported in rx_queue_offload_capa?
'port->rx_conf[]' is testpmd struct, and 'port->dev_conf.rxmode.offloads' values
are reflected to 'port->rx_conf[].offloads' for all queues.

We should set the offload in 'port->rx_conf[].offloads' if it is set in
'port->dev_conf.rxmode.offloads'.

If a port has capability for 'JUMBO_FRAME', 'port->rx_conf[].offloads' can have
it. And the port level capability is already checked above.
quoted
quoted
+       }
+
+       /* If JUMBO_FRAME is set MTU conversion done by ethdev layer,
+        * if unset do it here
+        */
+       if ((rx_offloads & DEV_RX_OFFLOAD_JUMBO_FRAME) == 0) {
+               ret = rte_eth_dev_set_mtu(portid,
+                               port->dev_conf.rxmode.max_rx_pkt_len - eth_overhead);
+               if (ret)
+                       printf("Failed to set MTU to %u for port %u\n",
+                               port->dev_conf.rxmode.max_rx_pkt_len - eth_overhead,
+                               portid);
+       }
+
+       return 0;
+}
+
Applied and tested with a few iterations of configuring max packet size
back and forth between jumbo and non-jumbo sizes, also tried setting
max packet size using the command-line option, all seems good based
on rx offloads and packet forwarding.

Two minor questions above, otherwise LGTM.
Thanks for testing. I will wait for more comments before new version.
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