mbuf: add function to generate raw Tx offload value

Operations to set/update bit-fields often cause compilers
to generate suboptimal code.
To help avoid such situation for tx_offload fields:
introduce new enum for tx_offload bit-fields lengths and offsets,
and new function to generate raw tx_offload value.
Add new test-case into UT for introduced function.

Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Acked-by: Akhil Goyal <akhil.goyal@nxp.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>

diff --git a/app/test/test_mbuf.c b/app/test/test_mbuf.c
index 9e82a20..030385e 100644 (file)
--- a/app/test/test_mbuf.c
+++ b/app/test/test_mbuf.c
@@ -27,6 +27,7 @@
 #include <rte_mbuf.h>
 #include <rte_random.h>
 #include <rte_cycles.h>
+#include <rte_malloc.h>
 
 #include "test.h"
 
@@ -1028,6 +1029,99 @@ test_mbuf_linearize_check(struct rte_mempool *pktmbuf_pool)
        return 0;
 }
 
+/*
+ * Helper function for test_tx_ofload
+ */
+static inline void
+set_tx_offload(struct rte_mbuf *mb, uint64_t il2, uint64_t il3, uint64_t il4,
+       uint64_t tso, uint64_t ol3, uint64_t ol2)
+{
+       mb->l2_len = il2;
+       mb->l3_len = il3;
+       mb->l4_len = il4;
+       mb->tso_segsz = tso;
+       mb->outer_l3_len = ol3;
+       mb->outer_l2_len = ol2;
+}
+
+static int
+test_tx_offload(void)
+{
+       struct rte_mbuf *mb;
+       uint64_t tm, v1, v2;
+       size_t sz;
+       uint32_t i;
+
+       static volatile struct {
+               uint16_t l2;
+               uint16_t l3;
+               uint16_t l4;
+               uint16_t tso;
+       } txof;
+
+       const uint32_t num = 0x10000;
+
+       txof.l2 = rte_rand() % (1 <<  RTE_MBUF_L2_LEN_BITS);
+       txof.l3 = rte_rand() % (1 <<  RTE_MBUF_L3_LEN_BITS);
+       txof.l4 = rte_rand() % (1 <<  RTE_MBUF_L4_LEN_BITS);
+       txof.tso = rte_rand() % (1 <<   RTE_MBUF_TSO_SEGSZ_BITS);
+
+       printf("%s started, tx_offload = {\n"
+               "\tl2_len=%#hx,\n"
+               "\tl3_len=%#hx,\n"
+               "\tl4_len=%#hx,\n"
+               "\ttso_segsz=%#hx,\n"
+               "\touter_l3_len=%#x,\n"
+               "\touter_l2_len=%#x,\n"
+               "};\n",
+               __func__,
+               txof.l2, txof.l3, txof.l4, txof.tso, txof.l3, txof.l2);
+
+       sz = sizeof(*mb) * num;
+       mb = rte_zmalloc(NULL, sz, RTE_CACHE_LINE_SIZE);
+       if (mb == NULL) {
+               printf("%s failed, out of memory\n", __func__);
+               return -ENOMEM;
+       }
+
+       memset(mb, 0, sz);
+       tm = rte_rdtsc_precise();
+
+       for (i = 0; i != num; i++)
+               set_tx_offload(mb + i, txof.l2, txof.l3, txof.l4,
+                       txof.tso, txof.l3, txof.l2);
+
+       tm = rte_rdtsc_precise() - tm;
+       printf("%s set tx_offload by bit-fields: %u iterations, %"
+               PRIu64 " cycles, %#Lf cycles/iter\n",
+               __func__, num, tm, (long double)tm / num);
+
+       v1 = mb[rte_rand() % num].tx_offload;
+
+       memset(mb, 0, sz);
+       tm = rte_rdtsc_precise();
+
+       for (i = 0; i != num; i++)
+               mb[i].tx_offload = rte_mbuf_tx_offload(txof.l2, txof.l3,
+                       txof.l4, txof.tso, txof.l3, txof.l2, 0);
+
+       tm = rte_rdtsc_precise() - tm;
+       printf("%s set raw tx_offload: %u iterations, %"
+               PRIu64 " cycles, %#Lf cycles/iter\n",
+               __func__, num, tm, (long double)tm / num);
+
+       v2 = mb[rte_rand() % num].tx_offload;
+
+       rte_free(mb);
+
+       printf("%s finished\n"
+               "expected tx_offload value: 0x%" PRIx64 ";\n"
+               "rte_mbuf_tx_offload value: 0x%" PRIx64 ";\n",
+               __func__, v1, v2);
+
+       return (v1 == v2) ? 0 : -EINVAL;
+}
+
 static int
 test_mbuf(void)
 {
@@ -1126,8 +1220,13 @@ test_mbuf(void)
                printf("test_mbuf_linearize_check() failed\n");
                goto err;
        }
-       ret = 0;
 
+       if (test_tx_offload() < 0) {
+               printf("test_tx_offload() failed\n");
+               goto err;
+       }
+
+       ret = 0;
 err:
        rte_mempool_free(pktmbuf_pool);
        rte_mempool_free(pktmbuf_pool2);

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 73daa81..f7886dc 100644 (file)
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -40,6 +40,7 @@
 #include <rte_atomic.h>
 #include <rte_prefetch.h>
 #include <rte_branch_prediction.h>
+#include <rte_byteorder.h>
 #include <rte_mbuf_ptype.h>
 
 #ifdef __cplusplus
@@ -479,6 +480,50 @@ struct rte_mbuf_sched {
        uint16_t reserved;   /**< Reserved. */
 }; /**< Hierarchical scheduler */
 
+/**
+ * enum for the tx_offload bit-fields lenghts and offsets.
+ * defines the layout of rte_mbuf tx_offload field.
+ */
+enum {
+       RTE_MBUF_L2_LEN_BITS = 7,
+       RTE_MBUF_L3_LEN_BITS = 9,
+       RTE_MBUF_L4_LEN_BITS = 8,
+       RTE_MBUF_TSO_SEGSZ_BITS = 16,
+       RTE_MBUF_OUTL3_LEN_BITS = 9,
+       RTE_MBUF_OUTL2_LEN_BITS = 7,
+       RTE_MBUF_TXOFLD_UNUSED_BITS = sizeof(uint64_t) * CHAR_BIT -
+               RTE_MBUF_L2_LEN_BITS -
+               RTE_MBUF_L3_LEN_BITS -
+               RTE_MBUF_L4_LEN_BITS -
+               RTE_MBUF_TSO_SEGSZ_BITS -
+               RTE_MBUF_OUTL3_LEN_BITS -
+               RTE_MBUF_OUTL2_LEN_BITS,
+#if RTE_BYTE_ORDER == RTE_BIG_ENDIAN
+       RTE_MBUF_L2_LEN_OFS =
+               sizeof(uint64_t) * CHAR_BIT - RTE_MBUF_L2_LEN_BITS
+       RTE_MBUF_L3_LEN_OFS = RTE_MBUF_L2_LEN_OFS - RTE_MBUF_L3_LEN_BITS,
+       RTE_MBUF_L4_LEN_OFS = RTE_MBUF_L3_LEN_OFS - RTE_MBUF_L4_LEN_BITS,
+       RTE_MBUF_TSO_SEGSZ_OFS = RTE_MBUF_L4_LEN_OFS - RTE_MBUF_TSO_SEGSZ_BITS,
+       RTE_MBUF_OUTL3_LEN_OFS =
+               RTE_MBUF_TSO_SEGSZ_OFS - RTE_MBUF_OUTL3_LEN_BITS,
+       RTE_MBUF_OUTL2_LEN_OFS =
+               RTE_MBUF_OUTL3_LEN_OFS - RTE_MBUF_OUTL2_LEN_BITS,
+       RTE_MBUF_TXOFLD_UNUSED_OFS =
+               RTE_MBUF_OUTL2_LEN_OFS - RTE_MBUF_TXOFLD_UNUSED_BITS,
+#else
+       RTE_MBUF_L2_LEN_OFS = 0,
+       RTE_MBUF_L3_LEN_OFS = RTE_MBUF_L2_LEN_OFS + RTE_MBUF_L2_LEN_BITS,
+       RTE_MBUF_L4_LEN_OFS = RTE_MBUF_L3_LEN_OFS + RTE_MBUF_L3_LEN_BITS,
+       RTE_MBUF_TSO_SEGSZ_OFS = RTE_MBUF_L4_LEN_OFS + RTE_MBUF_L4_LEN_BITS,
+       RTE_MBUF_OUTL3_LEN_OFS =
+               RTE_MBUF_TSO_SEGSZ_OFS + RTE_MBUF_TSO_SEGSZ_BITS,
+       RTE_MBUF_OUTL2_LEN_OFS =
+               RTE_MBUF_OUTL3_LEN_OFS + RTE_MBUF_OUTL3_LEN_BITS,
+       RTE_MBUF_TXOFLD_UNUSED_OFS =
+               RTE_MBUF_OUTL2_LEN_OFS + RTE_MBUF_OUTL2_LEN_BITS,
+#endif
+};
+
 /**
  * The generic rte_mbuf, containing a packet mbuf.
  */
@@ -640,19 +685,24 @@ struct rte_mbuf {
                uint64_t tx_offload;       /**< combined for easy fetch */
                __extension__
                struct {
-                       uint64_t l2_len:7;
+                       uint64_t l2_len:RTE_MBUF_L2_LEN_BITS;
                        /**< L2 (MAC) Header Length for non-tunneling pkt.
                         * Outer_L4_len + ... + Inner_L2_len for tunneling pkt.
                         */
-                       uint64_t l3_len:9; /**< L3 (IP) Header Length. */
-                       uint64_t l4_len:8; /**< L4 (TCP/UDP) Header Length. */
-                       uint64_t tso_segsz:16; /**< TCP TSO segment size */
+                       uint64_t l3_len:RTE_MBUF_L3_LEN_BITS;
+                       /**< L3 (IP) Header Length. */
+                       uint64_t l4_len:RTE_MBUF_L4_LEN_BITS;
+                       /**< L4 (TCP/UDP) Header Length. */
+                       uint64_t tso_segsz:RTE_MBUF_TSO_SEGSZ_BITS;
+                       /**< TCP TSO segment size */
 
                        /* fields for TX offloading of tunnels */
-                       uint64_t outer_l3_len:9; /**< Outer L3 (IP) Hdr Length. */
-                       uint64_t outer_l2_len:7; /**< Outer L2 (MAC) Hdr Length. */
+                       uint64_t outer_l3_len:RTE_MBUF_OUTL3_LEN_BITS;
+                       /**< Outer L3 (IP) Hdr Length. */
+                       uint64_t outer_l2_len:RTE_MBUF_OUTL2_LEN_BITS;
+                       /**< Outer L2 (MAC) Hdr Length. */
 
-                       /* uint64_t unused:8; */
+                       /* uint64_t unused:RTE_MBUF_TXOFLD_UNUSED_BITS; */
                };
        };
 
@@ -2243,6 +2293,43 @@ static inline int rte_pktmbuf_chain(struct rte_mbuf *head, struct rte_mbuf *tail
        return 0;
 }
 
+/*
+ * @warning
+ * @b EXPERIMENTAL: This API may change without prior notice.
+ *
+ * For given input values generate raw tx_offload value.
+ * Note that it is caller responsibility to make sure that input parameters
+ * don't exceed maximum bit-field values.
+ * @param il2
+ *   l2_len value.
+ * @param il3
+ *   l3_len value.
+ * @param il4
+ *   l4_len value.
+ * @param tso
+ *   tso_segsz value.
+ * @param ol3
+ *   outer_l3_len value.
+ * @param ol2
+ *   outer_l2_len value.
+ * @param unused
+ *   unused value.
+ * @return
+ *   raw tx_offload value.
+ */
+static __rte_always_inline uint64_t
+rte_mbuf_tx_offload(uint64_t il2, uint64_t il3, uint64_t il4, uint64_t tso,
+       uint64_t ol3, uint64_t ol2, uint64_t unused)
+{
+       return il2 << RTE_MBUF_L2_LEN_OFS |
+               il3 << RTE_MBUF_L3_LEN_OFS |
+               il4 << RTE_MBUF_L4_LEN_OFS |
+               tso << RTE_MBUF_TSO_SEGSZ_OFS |
+               ol3 << RTE_MBUF_OUTL3_LEN_OFS |
+               ol2 << RTE_MBUF_OUTL2_LEN_OFS |
+               unused << RTE_MBUF_TXOFLD_UNUSED_OFS;
+}
+
 /**
  * Validate general requirements for Tx offload in mbuf.
  *