>diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
>index 529debb..e3ee0b3 100644
>--- a/lib/librte_mbuf/rte_mbuf.h
>+++ b/lib/librte_mbuf/rte_mbuf.h
>@@ -842,6 +842,44 @@ struct rte_mbuf {
> uint16_t timesync;
> } __rte_cache_aligned;
>
>+/**
>+ * Prefetch the first part of the mbuf
>+ *
>+ * The first 64 bytes of the mbuf corresponds to fields that are used early
>+ * in the receive path. If the cache line of the architecture is higher than
>+ * 64B, the second part will also be prefetched.
>+ *
>+ * @param m
>+ * The pointer to the mbuf.
>+ */
>+static inline void
>+rte_mbuf_prefetch_part0(struct rte_mbuf *m)
>+{
>+ rte_prefetch0(&m->cacheline0);
>+}
>+
>+/**
>+ * Prefetch the second part of the mbuf
>+ *
>+ * The next 64 bytes of the mbuf corresponds to fields that are used in the
>+ * transmit path. If the cache line of the architecture is higher than 64B,
>+ * this function does nothing as it is expected that the full mbuf is
>+ * already in cache.
>+ *
>+ * @param m
>+ * The pointer to the mbuf.
>+ */
>+static inline void
>+rte_mbuf_prefetch_part1(struct rte_mbuf *m)
>+{
>+#if RTE_CACHE_LINE_SIZE == 64
>+ rte_prefetch0(&m->cacheline1);
>+#else
>+ RTE_SET_USED(m);
>+#endif
>+}
I am not super happy with the names here, but I understand that
rte_mbuf_prefetch_cacheline0() is a bit long. I could live with them being
longer if that makes more sense and adds to readability.
Another idea is to have only one function for both:
enum { MBUF_CACHELINE0 = 0, MBUF_CACHELINE1, MBUF_CACHELINES }; //
Optional enum if you want
static inline void
rte_mbuf_prefetch(struct rte_mbuf *m, unsigned cacheline) // Make sure we
add a comment about the constant value
{
if (cacheline == MBUF_CACHELINE0)
rte_prefetch0(&m->cacheline0);
else if (cacheline == MBUF_CACHELINE1)
rte_prefetch0(&m->cacheline1);
else {
rte_prefetch0(&m->cacheline0);
rte_prefetch0(&m->cacheline1);
}
}
I believe if you use constant value in the call for the cacheline variable then
the extra code should be optimized out. If not then what about a macro instead.
#define rte_mbuf_prefetch(m, c) \
do { \
if ((c) == MBUF_CACHELINE0) \
rte_prefetch0(&(m)->cacheline0); \
else if ((c) == MBUF_CACHELINE1) \
rte_prefetch0(&(m)->cacheline1); \
else { \
rte_prefetch0(&(m)->cacheline0); \
rte_prefetch0(&(m)->cacheline1); \
} \
} while((0))
Call like this:
rte_mbuf_prefetch(m, 0); // For cacheline 0
rte_mbuf_prefetch(m, 1); // For cacheline 1
rte_mbuf_prefetch(m, 2); // For cacheline 0 and 1
We could have another routine:
rte_mbuf_prefetch_data(m, 0); // Prefetch the first cacheline of the
packet data.
Just a thought and I did not test the above code, so I hope it works that way.
I noticed something like this in the linux spinlock code a few years ago.
>+
>+
> static inline uint16_t rte_pktmbuf_priv_size(struct rte_mempool *mp);
>
> /**
>--
>2.8.0.rc3
>
>
Regards,
Keith
