From 56e62d88c52af87c35c6afa638c56984ec50299c Mon Sep 17 00:00:00 2001 From: Donald Sharp Date: Mon, 5 Feb 2024 14:15:29 -0500 Subject: [PATCH] zebra: Reorg `struct route_entry` to have important bits first The `struct route_entry` had items that were almost never used at the front of the data structure resulting in items that would be loaded first into memory that were never used. Let's reorg a tiny bit and put all the frequently used items in the first cache line. I'm sure people will notice .000000001 speedup new layout: sharpd@eva /w/h/s/frr1 (reorg_route_entry)> /home/sharpd/pahole/build/pahole --reorganize --show_reorg_steps -C route_entry zebra/.libs/zebra struct route_entry { struct re_list_item next; /* 0 8 */ struct nhg_hash_entry * nhe; /* 8 8 */ uint32_t nhe_id; /* 16 4 */ uint32_t nhe_installed_id; /* 20 4 */ int type; /* 24 4 */ vrf_id_t vrf_id; /* 28 4 */ uint32_t table; /* 32 4 */ uint32_t metric; /* 36 4 */ uint32_t mtu; /* 40 4 */ uint32_t nexthop_mtu; /* 44 4 */ uint32_t flags; /* 48 4 */ uint32_t status; /* 52 4 */ uint32_t dplane_sequence; /* 56 4 */ uint16_t instance; /* 60 2 */ uint8_t distance; /* 62 1 */ /* XXX 1 byte hole, try to pack */ /* --- cacheline 1 boundary (64 bytes) --- */ route_tag_t tag; /* 64 4 */ /* XXX 4 bytes hole, try to pack */ time_t uptime; /* 72 8 */ struct re_opaque * opaque; /* 80 8 */ struct nexthop_group fib_ng; /* 88 32 */ struct nexthop_group fib_backup_ng; /* 120 32 */ /* size: 152, cachelines: 3, members: 20 */ /* sum members: 147, holes: 2, sum holes: 5 */ /* last cacheline: 24 bytes */ }; Signed-off-by: Donald Sharp --- zebra/rib.h | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/zebra/rib.h b/zebra/rib.h index 4c817eca71c7..a721f4bac456 100644 --- a/zebra/rib.h +++ b/zebra/rib.h @@ -85,25 +85,12 @@ struct route_entry { */ struct nhg_hash_entry *nhe; - /* Nexthop group from FIB (optional), reflecting what is actually - * installed in the FIB if that differs. The 'backup' group is used - * when backup nexthops are present in the route's nhg. - */ - struct nexthop_group fib_ng; - struct nexthop_group fib_backup_ng; - /* Nexthop group hash entry IDs. The "installed" id is the id * used in linux/netlink, if available. */ uint32_t nhe_id; uint32_t nhe_installed_id; - /* Tag */ - route_tag_t tag; - - /* Uptime. */ - time_t uptime; - /* Type of this route. */ int type; @@ -160,7 +147,20 @@ struct route_entry { /* Distance. */ uint8_t distance; + /* Tag */ + route_tag_t tag; + + /* Uptime. */ + time_t uptime; + struct re_opaque *opaque; + + /* Nexthop group from FIB (optional), reflecting what is actually + * installed in the FIB if that differs. The 'backup' group is used + * when backup nexthops are present in the route's nhg. + */ + struct nexthop_group fib_ng; + struct nexthop_group fib_backup_ng; }; #define RIB_SYSTEM_ROUTE(R) RSYSTEM_ROUTE((R)->type)