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* [dpdk-dev] rte_mbuf library likely()/unlikely()
@ 2018-07-23 13:53 Morten Brørup
  2018-07-23 17:37 ` Stephen Hemminger
  2018-07-23 17:51 ` Honnappa Nagarahalli
  0 siblings, 2 replies; 11+ messages in thread
From: Morten Brørup @ 2018-07-23 13:53 UTC (permalink / raw)
  To: Olivier Matz; +Cc: dev

Hi Olivier,

 

I noticed that __rte_pktmbuf_read() could do with an unlikely(), so I went through the entire library. Here are my suggested modifications.

 

 

diff -bu rte_mbuf.c.orig rte_mbuf.c

--- rte_mbuf.c.orig     2018-07-23 15:13:22.000000000 +0200

+++ rte_mbuf.c  2018-07-23 15:32:53.000000000 +0200

@@ -173,19 +173,19 @@

{

        unsigned int nb_segs, pkt_len;

 

-       if (m == NULL)

+       if (unlikely(m == NULL))

                rte_panic("mbuf is NULL\n");

 

        /* generic checks */

-       if (m->pool == NULL)

+       if (unlikely(m->pool == NULL))

                rte_panic("bad mbuf pool\n");

-       if (m->buf_iova == 0)

+       if (unlikely(m->buf_iova == 0))

                rte_panic("bad IO addr\n");

-       if (m->buf_addr == NULL)

+       if (unlikely(m->buf_addr == NULL))

                rte_panic("bad virt addr\n");

 

        uint16_t cnt = rte_mbuf_refcnt_read(m);

-       if ((cnt == 0) || (cnt == UINT16_MAX))

+       if (unlikely((cnt == 0) || (cnt == UINT16_MAX)))

                rte_panic("bad ref cnt\n");

 

        /* nothing to check for sub-segments */

@@ -193,7 +193,7 @@

                return;

 

        /* data_len is supposed to be not more than pkt_len */

-       if (m->data_len > m->pkt_len)

+       if (unlikely(m->data_len > m->pkt_len))

                rte_panic("bad data_len\n");

 

        nb_segs = m->nb_segs;

@@ -204,9 +204,9 @@

                pkt_len -= m->data_len;

        } while ((m = m->next) != NULL);

 

-       if (nb_segs)

+       if (unlikely(nb_segs))

                rte_panic("bad nb_segs\n");

-       if (pkt_len)

+       if (unlikely(pkt_len))

                rte_panic("bad pkt_len\n");

}

 

@@ -249,7 +249,7 @@

        const struct rte_mbuf *seg = m;

        uint32_t buf_off = 0, copy_len;

 

-       if (off + len > rte_pktmbuf_pkt_len(m))

+       if (unlikely(off + len > rte_pktmbuf_pkt_len(m)))

                return NULL;

 

        while (off >= rte_pktmbuf_data_len(seg)) {

@@ -257,7 +257,7 @@

                seg = seg->next;

        }

 

-       if (off + len <= rte_pktmbuf_data_len(seg))

+       if (likely(off + len <= rte_pktmbuf_data_len(seg)))

                return rte_pktmbuf_mtod_offset(seg, char *, off);

 

        /* rare case: header is split among several segments */

@@ -344,7 +344,7 @@

        unsigned int i;

        int ret;

 

-       if (buflen == 0)

+       if (unlikely(buflen == 0))

                return -1;

 

        buf[0] = '\0';

@@ -355,9 +355,9 @@

                if (name == NULL)

                        name = rx_flags[i].default_name;

                ret = snprintf(buf, buflen, "%s ", name);

-               if (ret < 0)

+               if (unlikely(ret < 0))

                        return -1;

-               if ((size_t)ret >= buflen)

+               if (unlikely((size_t)ret >= buflen))

                        return -1;

                buf += ret;

                buflen -= ret;

@@ -440,7 +440,7 @@

        unsigned int i;

        int ret;

 

-       if (buflen == 0)

+       if (unlikely(buflen == 0))

                return -1;

 

        buf[0] = '\0';

@@ -451,9 +451,9 @@

                if (name == NULL)

                        name = tx_flags[i].default_name;

                ret = snprintf(buf, buflen, "%s ", name);

-               if (ret < 0)

+               if (unlikely(ret < 0))

                        return -1;

-               if ((size_t)ret >= buflen)

+               if (unlikely((size_t)ret >= buflen))

                        return -1;

                buf += ret;

                buflen -= ret;

 

 

diff -bu rte_mbuf.h.orig rte_mbuf.h

--- rte_mbuf.h.orig     2018-07-23 15:13:26.000000000 +0200

+++ rte_mbuf.h  2018-07-23 15:24:25.000000000 +0200

@@ -1007,7 +1007,7 @@

{

        struct rte_mbuf *m;

 

-       if (rte_mempool_get(mp, (void **)&m) < 0)

+       if (unlikely(rte_mempool_get(mp, (void **)&m) < 0))

                return NULL;

        MBUF_RAW_ALLOC_CHECK(m);

        return m;

@@ -1268,7 +1268,7 @@

static inline struct rte_mbuf *rte_pktmbuf_alloc(struct rte_mempool *mp)

{

        struct rte_mbuf *m;

-       if ((m = rte_mbuf_raw_alloc(mp)) != NULL)

+       if (likely((m = rte_mbuf_raw_alloc(mp)) != NULL))

                rte_pktmbuf_reset(m);

        return m;

}

@@ -1696,7 +1696,7 @@

{

        struct rte_mbuf *m_next;

 

-       if (m != NULL)

+       if (likely(m != NULL))

                __rte_mbuf_sanity_check(m, 1);

 

        while (m != NULL) {

@@ -2099,7 +2099,7 @@

        struct rte_mbuf *cur_tail;

 

        /* Check for number-of-segments-overflow */

-       if (head->nb_segs + tail->nb_segs > RTE_MBUF_MAX_NB_SEGS)

+       if (unlikely(head->nb_segs + tail->nb_segs > RTE_MBUF_MAX_NB_SEGS))

                return -EOVERFLOW;

 

        /* Chain 'tail' onto the old tail */

@@ -2147,28 +2147,28 @@

                                  m->outer_l3_len;

 

        /* Headers are fragmented */

-       if (rte_pktmbuf_data_len(m) < inner_l3_offset + m->l3_len + m->l4_len)

+       if (unlikely(rte_pktmbuf_data_len(m) < inner_l3_offset + m->l3_len + m->l4_len))

                return -ENOTSUP;

 

        /* IP checksum can be counted only for IPv4 packet */

-       if ((ol_flags & PKT_TX_IP_CKSUM) && (ol_flags & PKT_TX_IPV6))

+       if (unlikely((ol_flags & PKT_TX_IP_CKSUM) && (ol_flags & PKT_TX_IPV6)))

                return -EINVAL;

 

        /* IP type not set when required */

        if (ol_flags & (PKT_TX_L4_MASK | PKT_TX_TCP_SEG))

-               if (!(ol_flags & (PKT_TX_IPV4 | PKT_TX_IPV6)))

+               if (unlikely(!(ol_flags & (PKT_TX_IPV4 | PKT_TX_IPV6))))

                        return -EINVAL;

 

        /* Check requirements for TSO packet */

        if (ol_flags & PKT_TX_TCP_SEG)

-               if ((m->tso_segsz == 0) ||

+               if (unlikely((m->tso_segsz == 0) ||

                                ((ol_flags & PKT_TX_IPV4) &&

-                               !(ol_flags & PKT_TX_IP_CKSUM)))

+                               !(ol_flags & PKT_TX_IP_CKSUM))))

                        return -EINVAL;

 

        /* PKT_TX_OUTER_IP_CKSUM set for non outer IPv4 packet. */

-       if ((ol_flags & PKT_TX_OUTER_IP_CKSUM) &&

-                       !(ol_flags & PKT_TX_OUTER_IPV4))

+       if (unlikely((ol_flags & PKT_TX_OUTER_IP_CKSUM) &&

+                       !(ol_flags & PKT_TX_OUTER_IPV4)))

                return -EINVAL;

 

        return 0;

 

 

diff -bu rte_mbuf_ptype.c.orig rte_mbuf_ptype.c

--- rte_mbuf_ptype.c.orig       2018-07-23 15:45:49.000000000 +0200

+++ rte_mbuf_ptype.c    2018-07-23 15:44:59.000000000 +0200

@@ -118,15 +118,15 @@

{

        int ret;

 

-       if (buflen == 0)

+       if (unlikely(buflen == 0))

                return -1;

 

        buf[0] = '\0';

        if ((ptype & RTE_PTYPE_ALL_MASK) == RTE_PTYPE_UNKNOWN) {

                ret = snprintf(buf, buflen, "UNKNOWN");

-               if (ret < 0)

+               if (unlikely(ret < 0))

                        return -1;

-               if ((size_t)ret >= buflen)

+               if (unlikely((size_t)ret >= buflen))

                       return -1;

                return 0;

        }

@@ -134,9 +134,9 @@

        if ((ptype & RTE_PTYPE_L2_MASK) != 0) {

                ret = snprintf(buf, buflen, "%s ",

                        rte_get_ptype_l2_name(ptype));

-               if (ret < 0)

+               if (unlikely(ret < 0))

                        return -1;

-               if ((size_t)ret >= buflen)

+               if (unlikely((size_t)ret >= buflen))

                        return -1;

                buf += ret;

                buflen -= ret;

@@ -144,9 +144,9 @@

        if ((ptype & RTE_PTYPE_L3_MASK) != 0) {

                ret = snprintf(buf, buflen, "%s ",

                        rte_get_ptype_l3_name(ptype));

-               if (ret < 0)

+               if (unlikely(ret < 0))

                        return -1;

-               if ((size_t)ret >= buflen)

+               if (unlikely((size_t)ret >= buflen))

                        return -1;

                buf += ret;

                buflen -= ret;

@@ -154,9 +154,9 @@

        if ((ptype & RTE_PTYPE_L4_MASK) != 0) {

                ret = snprintf(buf, buflen, "%s ",

                        rte_get_ptype_l4_name(ptype));

-               if (ret < 0)

+               if (unlikely(ret < 0))

                        return -1;

-               if ((size_t)ret >= buflen)

+               if (unlikely((size_t)ret >= buflen))

                        return -1;

                buf += ret;

                buflen -= ret;

@@ -164,9 +164,9 @@

        if ((ptype & RTE_PTYPE_TUNNEL_MASK) != 0) {

                ret = snprintf(buf, buflen, "%s ",

                        rte_get_ptype_tunnel_name(ptype));

-               if (ret < 0)

+               if (unlikely(ret < 0))

                        return -1;

-               if ((size_t)ret >= buflen)

+               if (unlikely((size_t)ret >= buflen))

                        return -1;

                buf += ret;

                buflen -= ret;

@@ -174,9 +174,9 @@

        if ((ptype & RTE_PTYPE_INNER_L2_MASK) != 0) {

                ret = snprintf(buf, buflen, "%s ",

                        rte_get_ptype_inner_l2_name(ptype));

-               if (ret < 0)

+               if (unlikely(ret < 0))

                        return -1;

-               if ((size_t)ret >= buflen)

+               if (unlikely((size_t)ret >= buflen))

                        return -1;

                buf += ret;

                buflen -= ret;

@@ -184,9 +184,9 @@

        if ((ptype & RTE_PTYPE_INNER_L3_MASK) != 0) {

                ret = snprintf(buf, buflen, "%s ",

                        rte_get_ptype_inner_l3_name(ptype));

-               if (ret < 0)

+               if (unlikely(ret < 0))

                        return -1;

-               if ((size_t)ret >= buflen)

+               if (unlikely((size_t)ret >= buflen))

                        return -1;

                buf += ret;

                buflen -= ret;

@@ -194,9 +194,9 @@

        if ((ptype & RTE_PTYPE_INNER_L4_MASK) != 0) {

                ret = snprintf(buf, buflen, "%s ",

                        rte_get_ptype_inner_l4_name(ptype));

-               if (ret < 0)

+               if (unlikely(ret < 0))

                        return -1;

-               if ((size_t)ret >= buflen)

+               if (unlikely((size_t)ret >= buflen))

                        return -1;

                buf += ret;

                buflen -= ret;

 

 

 

Med venlig hilsen / kind regards

 

Morten Brørup

CTO

 

 

SmartShare Systems A/S

Tonsbakken 16-18

DK-2740 Skovlunde

Denmark

 

Office      +45 70 20 00 93

Direct      +45 89 93 50 22

Mobile     +45 25 40 82 12

 

mb@smartsharesystems.com <mailto:mb@smartsharesystems.com> 

www.smartsharesystems.com <https://www.smartsharesystems.com/> 

 


^ permalink raw reply	[flat|nested] 11+ messages in thread

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Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-07-23 13:53 [dpdk-dev] rte_mbuf library likely()/unlikely() Morten Brørup
2018-07-23 17:37 ` Stephen Hemminger
2018-07-23 18:59   ` Morten Brørup
2018-07-23 19:45     ` Stephen Hemminger
2018-07-23 17:51 ` Honnappa Nagarahalli
2018-07-23 19:09   ` Morten Brørup
2018-07-23 22:40     ` Wiles, Keith
2018-07-24  7:29       ` Olivier Matz
2018-07-24  8:13         ` Morten Brørup
2018-07-24 11:31           ` Van Haaren, Harry
2018-07-24 13:02             ` Wiles, Keith

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