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authorDamjan Marion <damarion@cisco.com>2018-05-10 13:40:44 +0200
committerDave Barach <openvpp@barachs.net>2018-05-10 17:16:56 +0000
commit1105600416e0560cb05120a22e0a2e7359a13665 (patch)
treeacf1df08de42344c380473d81886864e662890cf /src/vnet/devices
parent132dc49ee847a3e3b644de8b36499d73e8a8d37e (diff)
vppinfra: use count_trailing_zeros in sparse_vec_index
It is much cheaper to use ctzll than to do shift,subtract and mask in likely case when we are looking for 1st set bit in the uword. Change-Id: I31954081571978878c7098bafad0c85a91755fa2 Signed-off-by: Damjan Marion <damarion@cisco.com>
Diffstat (limited to 'src/vnet/devices')
-rw-r--r--src/vnet/devices/virtio/vhost-user.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/src/vnet/devices/virtio/vhost-user.c b/src/vnet/devices/virtio/vhost-user.c
index c1fca441fa5..7e10a60f5fb 100644
--- a/src/vnet/devices/virtio/vhost-user.c
+++ b/src/vnet/devices/virtio/vhost-user.c
@@ -248,8 +248,8 @@ map_guest_mem (vhost_user_intf_t * vui, uword addr, u32 * hint)
r = _mm_blend_epi16 (r, _mm_and_si128 (rl, rh), 0x88);
r = _mm_shuffle_epi8 (r, _mm_set_epi64x (0, 0x0e060c040a020800));
- i = __builtin_ctzll (_mm_movemask_epi8 (r) |
- (1 << VHOST_MEMORY_MAX_NREGIONS));
+ i = count_trailing_zeros (_mm_movemask_epi8 (r) |
+ (1 << VHOST_MEMORY_MAX_NREGIONS));
if (i < vui->nregions)
{
@@ -275,7 +275,7 @@ map_guest_mem (vhost_user_intf_t * vui, uword addr, u32 * hint)
if (u32)
{
- i = __builtin_ctzll (u32);
+ i = count_trailing_zeros (u32);
goto vhost_map_guest_mem_done;
}
@@ -290,7 +290,7 @@ map_guest_mem (vhost_user_intf_t * vui, uword addr, u32 * hint)
if (u32)
{
- i = __builtin_ctzll (u32);
+ i = count_trailing_zeros (u32);
goto vhost_map_guest_mem_done;
}
@@ -305,7 +305,7 @@ map_guest_mem (vhost_user_intf_t * vui, uword addr, u32 * hint)
if (u32)
{
- i = __builtin_ctzll (u32);
+ i = count_trailing_zeros (u32);
goto vhost_map_guest_mem_done;
}
@@ -318,7 +318,7 @@ map_guest_mem (vhost_user_intf_t * vui, uword addr, u32 * hint)
u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 0) & 0x1) << 6);
u32 |= ((vgetq_lane_u8 (vreinterpretq_u8_u64 (r), 8) & 0x1) << 7);
- i = __builtin_ctzll (u32 | (1 << VHOST_MEMORY_MAX_NREGIONS));
+ i = count_trailing_zeros (u32 | (1 << VHOST_MEMORY_MAX_NREGIONS));
vhost_map_guest_mem_done:
if (i < vui->nregions)