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udp: align udp_encap_t_ to 2 cachelines

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Based on the comments in the struct, udp_encap_t_ is meant to span 2
cachelines. Due to the 64 bit alignment of dpo_id_t, the struct spanned
3 cachelines. This caused fetching ue_ip_proto to trigger an additional
cache miss. This patch rearranges the ordering of the struct fields
so that udp_encap_t_ only spans 2 cachelines as intended.

before:
(gdb) print (int)&((struct udp_encap_t_*)0)->cacheline1
$8 = 128

after:
(gdb) print (int)&((struct udp_encap_t_*)0)->cacheline1
$1 = 64

Type: fix
Signed-off-by: Vadym Martsynovskyy <vmartsyn@fb.com>
Change-Id: I066c08654d4a8ef3e2d3954e957d4c5d382b209f
(cherry picked from commit 42386fc974148f812ef3eb73ff09a603caa23565)
This commit is contained in:
Vadym Martsynovskyy
2020-06-12 09:50:50 -07:00
committed by Andrew Yourtchenko
parent 86a5a5d5c2
commit 347a225866
1 changed files with 5 additions and 5 deletions
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10
src/vnet/udp/udp_encap.h
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@ -67,16 +67,16 @@ typedef struct udp_encap_t_
} __attribute__ ((packed)) ip6; } __attribute__ ((packed)) ip6;
} __attribute__ ((packed)) ue_hdrs; } __attribute__ ((packed)) ue_hdrs;
/**
* Flags controlling fixup behaviour
*/
udp_encap_fixup_flags_t ue_flags;
/** /**
* The DPO used to forward to the next node in the VLIB graph * The DPO used to forward to the next node in the VLIB graph
*/ */
dpo_id_t ue_dpo; dpo_id_t ue_dpo;
/**
* Flags controlling fixup behaviour
*/
udp_encap_fixup_flags_t ue_flags;
/** /**
* the protocol of the IP header imposed * the protocol of the IP header imposed
*/ */