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authorBenoît Ganne <bganne@cisco.com>2019-03-01 14:14:10 +0100
committerDamjan Marion <dmarion@me.com>2019-03-26 10:06:57 +0000
commit4af1a7f938207f713c249270ed98a0c12f72cd3f (patch)
tree42c93b22e20228641de844d553819f400676cc5e /src/vnet/adj
parent50d5069a80fd763f4270d61d991febbdfa88aed3 (diff)
Simplify adjacency rewrite code
Using memcpy instead of complex specific copy logic. This simplify the implementation and also improve perf slightly. Also move adjacency data from tail to head of buffer, which improves cache locality (header and data share the same cacheline) Finally, fix VxLAN which used to workaround vnet_rewrite logic. Change-Id: I770ddad9846f7ee505aa99ad417e6a61d5cbbefa Signed-off-by: Benoît Ganne <bganne@cisco.com>
Diffstat (limited to 'src/vnet/adj')
-rw-r--r--src/vnet/adj/rewrite.c30
-rw-r--r--src/vnet/adj/rewrite.h138
2 files changed, 26 insertions, 142 deletions
diff --git a/src/vnet/adj/rewrite.c b/src/vnet/adj/rewrite.c
index 975dc4ab817..95671b06930 100644
--- a/src/vnet/adj/rewrite.c
+++ b/src/vnet/adj/rewrite.c
@@ -40,30 +40,6 @@
#include <vnet/vnet.h>
#include <vnet/ip/lookup.h>
-void
-vnet_rewrite_copy_slow_path (vnet_rewrite_data_t * p0,
- vnet_rewrite_data_t * rw0,
- word n_left, uword most_likely_size)
-{
- uword n_done =
- round_pow2 (most_likely_size, sizeof (rw0[0])) / sizeof (rw0[0]);
-
- p0 -= n_done;
- rw0 -= n_done;
-
- /* As we enter the cleanup loop, p0 and rw0 point to the last chunk written
- by the fast path. Hence, the constant 1, which the
- vnet_rewrite_copy_one macro renders as p0[-1] = rw0[-1]. */
-
- while (n_left > 0)
- {
- vnet_rewrite_copy_one (p0, rw0, 1);
- p0--;
- rw0--;
- n_left--;
- }
-}
-
u8 *
format_vnet_rewrite (u8 * s, va_list * args)
{
@@ -72,6 +48,8 @@ format_vnet_rewrite (u8 * s, va_list * args)
CLIB_UNUSED (u32 indent) = va_arg (*args, u32);
vnet_main_t *vnm = vnet_get_main ();
+ ASSERT (rw->data_bytes <= max_data_bytes);
+
if (rw->sw_if_index != ~0)
{
vnet_sw_interface_t *si;
@@ -86,9 +64,7 @@ format_vnet_rewrite (u8 * s, va_list * args)
/* Format rewrite string. */
if (rw->data_bytes > 0)
- s = format (s, " %U",
- format_hex_bytes,
- rw->data + max_data_bytes - rw->data_bytes, rw->data_bytes);
+ s = format (s, " %U", format_hex_bytes, rw->data, rw->data_bytes);
return s;
}
diff --git a/src/vnet/adj/rewrite.h b/src/vnet/adj/rewrite.h
index 32781134ecc..05a722fc764 100644
--- a/src/vnet/adj/rewrite.h
+++ b/src/vnet/adj/rewrite.h
@@ -131,8 +131,8 @@ vnet_rewrite_set_data_internal (vnet_rewrite_header_t * rw,
ASSERT ((data_bytes >= 0) && (data_bytes < max_size));
rw->data_bytes = data_bytes;
- clib_memcpy_fast (rw->data + max_size - data_bytes, data, data_bytes);
- clib_memset (rw->data, 0xfe, max_size - data_bytes);
+ clib_memcpy_fast (rw->data, data, data_bytes);
+ clib_memset (rw->data + data_bytes, 0xfe, max_size - data_bytes);
}
#define vnet_rewrite_set_data(rw,data,data_bytes) \
@@ -145,76 +145,28 @@ always_inline void *
vnet_rewrite_get_data_internal (vnet_rewrite_header_t * rw, int max_size)
{
ASSERT (rw->data_bytes <= max_size);
- return rw->data + max_size - rw->data_bytes;
+ return rw->data;
}
#define vnet_rewrite_get_data(rw) \
vnet_rewrite_get_data_internal (&((rw).rewrite_header), sizeof ((rw).rewrite_data))
always_inline void
-vnet_rewrite_copy_one (vnet_rewrite_data_t * p0, vnet_rewrite_data_t * rw0,
- int i)
-{
- p0[-i] = rw0[-i];
-}
-
-void vnet_rewrite_copy_slow_path (vnet_rewrite_data_t * p0,
- vnet_rewrite_data_t * rw0,
- word n_left, uword most_likely_size);
-
-/* *INDENT-OFF* */
-typedef CLIB_PACKED (struct {
- u64 a;
- u32 b;
- u16 c;
-}) eh_copy_t;
-/* *INDENT-ON* */
-
-always_inline void
_vnet_rewrite_one_header (vnet_rewrite_header_t * h0,
void *packet0, int max_size, int most_likely_size)
{
- vnet_rewrite_data_t *p0 = packet0;
- vnet_rewrite_data_t *rw0 = (vnet_rewrite_data_t *) (h0->data + max_size);
- word n_left0;
-
/* 0xfefe => poisoned adjacency => crash */
ASSERT (h0->data_bytes != 0xfefe);
-
- if (PREDICT_TRUE (h0->data_bytes == sizeof (eh_copy_t)))
+ if (PREDICT_TRUE (most_likely_size == h0->data_bytes))
{
- eh_copy_t *s, *d;
- s = (eh_copy_t *) (h0->data + max_size - sizeof (eh_copy_t));
- d = (eh_copy_t *) (((u8 *) packet0) - sizeof (eh_copy_t));
- clib_memcpy (d, s, sizeof (eh_copy_t));
- return;
+ clib_memcpy_fast ((u8 *) packet0 - most_likely_size,
+ h0->data, most_likely_size);
+ }
+ else
+ {
+ clib_memcpy_fast ((u8 *) packet0 - h0->data_bytes,
+ h0->data, h0->data_bytes);
}
- /*
- * Stop now if the data_bytes field is zero, to avoid the cache
- * miss consequences of spraying [functionally harmless] junk into
- * un-prefetched rewrite space.
- */
- if (PREDICT_FALSE (h0->data_bytes == 0))
- return;
-
-#define _(i) \
- do { \
- if (most_likely_size > ((i)-1)*sizeof (vnet_rewrite_data_t)) \
- vnet_rewrite_copy_one (p0, rw0, (i)); \
- } while (0)
-
- _(4);
- _(3);
- _(2);
- _(1);
-
-#undef _
-
- n_left0 = (int)
- (((int) h0->data_bytes - most_likely_size) + (sizeof (rw0[0]) - 1))
- / (int) sizeof (rw0[0]);
- if (PREDICT_FALSE (n_left0 > 0))
- vnet_rewrite_copy_slow_path (p0, rw0, n_left0, most_likely_size);
}
always_inline void
@@ -223,68 +175,24 @@ _vnet_rewrite_two_headers (vnet_rewrite_header_t * h0,
void *packet0,
void *packet1, int max_size, int most_likely_size)
{
- vnet_rewrite_data_t *p0 = packet0;
- vnet_rewrite_data_t *p1 = packet1;
- vnet_rewrite_data_t *rw0 = (vnet_rewrite_data_t *) (h0->data + max_size);
- vnet_rewrite_data_t *rw1 = (vnet_rewrite_data_t *) (h1->data + max_size);
- word n_left0, n_left1;
- int slow_path;
-
/* 0xfefe => poisoned adjacency => crash */
ASSERT (h0->data_bytes != 0xfefe);
ASSERT (h1->data_bytes != 0xfefe);
-
- /* Arithmetic calculation: bytes0 == bytes1 == 14 */
- slow_path = h0->data_bytes ^ h1->data_bytes;
- slow_path += h0->data_bytes ^ sizeof (eh_copy_t);
-
- if (PREDICT_TRUE (slow_path == 0))
+ if (PREDICT_TRUE
+ (most_likely_size == h0->data_bytes
+ && most_likely_size == h1->data_bytes))
{
- eh_copy_t *s0, *d0, *s1, *d1;
- s0 = (eh_copy_t *) (h0->data + max_size - sizeof (eh_copy_t));
- d0 = (eh_copy_t *) (((u8 *) packet0) - sizeof (eh_copy_t));
- clib_memcpy (d0, s0, sizeof (eh_copy_t));
- s1 = (eh_copy_t *) (h1->data + max_size - sizeof (eh_copy_t));
- d1 = (eh_copy_t *) (((u8 *) packet1) - sizeof (eh_copy_t));
- clib_memcpy (d1, s1, sizeof (eh_copy_t));
- return;
+ clib_memcpy_fast ((u8 *) packet0 - most_likely_size,
+ h0->data, most_likely_size);
+ clib_memcpy_fast ((u8 *) packet1 - most_likely_size,
+ h1->data, most_likely_size);
}
-
- /*
- * Stop now if both rewrite data_bytes fields are zero, to avoid the cache
- * miss consequences of spraying [functionally harmless] junk into
- * un-prefetched rewrite space.
- */
- if (PREDICT_FALSE (h0->data_bytes + h1->data_bytes == 0))
- return;
-
-#define _(i) \
- do { \
- if (most_likely_size > ((i)-1)*sizeof (vnet_rewrite_data_t)) \
- { \
- vnet_rewrite_copy_one (p0, rw0, (i)); \
- vnet_rewrite_copy_one (p1, rw1, (i)); \
- } \
- } while (0)
-
- _(4);
- _(3);
- _(2);
- _(1);
-
-#undef _
-
- n_left0 = (int)
- (((int) h0->data_bytes - most_likely_size) + (sizeof (rw0[0]) - 1))
- / (int) sizeof (rw0[0]);
- n_left1 = (int)
- (((int) h1->data_bytes - most_likely_size) + (sizeof (rw1[0]) - 1))
- / (int) sizeof (rw1[0]);
-
- if (PREDICT_FALSE (n_left0 > 0 || n_left1 > 0))
+ else
{
- vnet_rewrite_copy_slow_path (p0, rw0, n_left0, most_likely_size);
- vnet_rewrite_copy_slow_path (p1, rw1, n_left1, most_likely_size);
+ clib_memcpy_fast ((u8 *) packet0 - h0->data_bytes,
+ h0->data, h0->data_bytes);
+ clib_memcpy_fast ((u8 *) packet1 - h1->data_bytes,
+ h1->data, h1->data_bytes);
}
}