回复: af_packet can't send packet more than framecnt

[hfli at netitest.com]

Hi,

The issue has been resolved when I patched new code from dpdk 22.12, my dpdk
version is 19.11

Index: rte_eth_af_packet.c
===================================================================
--- rte_eth_af_packet.c (版本 44115)
+++ rte_eth_af_packet.c (版本 44128)
@@ -169,6 +169,29 @@
 }
 
 /*
+ * Check if there is an available frame in the ring
+ */
+static inline int
+tx_ring_status_available(uint32_t tp_status)
+{
+       /*
+        * We eliminate the timestamp status from the packet status.
+        * This should only matter if timestamping is enabled on the socket,
+        * but there is a bug in the kernel which is fixed in newer
releases.
+        *
+        * See the following kernel commit for reference:
+        *     commit 171c3b151118a2fe0fc1e2a9d1b5a1570cfe82d2
+        *     net: packetmmap: fix only tx timestamp on request
+        */
+       tp_status &= ~(TP_STATUS_TS_SOFTWARE | TP_STATUS_TS_RAW_HARDWARE);
+
+       if (tp_status == TP_STATUS_AVAILABLE)
+        return 1;
+
+    return 0;
+}
+
+/*
  * Callback to handle sending packets through a real NIC.
  */
 static uint16_t
@@ -213,7 +236,7 @@
                }
 
                /* point at the next incoming frame */
-               if (ppd->tp_status != TP_STATUS_AVAILABLE) {
+               if (!tx_ring_status_available(ppd->tp_status)) {
                        if (poll(&pfd, 1, -1) < 0)
                                break;
 
@@ -236,7 +259,7 @@
                 *
                 * This results in poll() returning POLLOUT.
                 */
-               if (ppd->tp_status != TP_STATUS_AVAILABLE)
+               if (!tx_ring_status_available(ppd->tp_status))
                        break;
 
                /* copy the tx frame data */


Thanks,
Haifeng

-----邮件原件-----
发件人: hfli at netitest.com <hfli at netitest.com> 
发送时间: 2023年3月20日 11:32
收件人: 'dev at dpdk.org' <dev at dpdk.org>
主题: af_packet can't send packet more than framecnt

Hi,

I used af_packet interface, but found only can send packets successfully
less than framecnt argument. 

E.g. if I pass “--vdev=eth_af_packet0,iface=tap0,blocksz=4096,framesz=2048,
framecnt=512,qpairs=1,qdisc_bypass=0” to DPDK, the rte_eth_tx_burst only
return 1 for 512 times, after that it always return 0.
If I pass
“--vdev=eth_af_packet0,iface=tap0,blocksz=4096,framesz=2048,framecnt=1024,q
pairs=1,qdisc_bypass=0” to DPDK, the rte_eth_tx_burst only return 1 for
1024 times, after that it always return 0.

BTW, I use busy loop mode in project, Is there any help for this?



Thanks so much
Haifeng