diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs index 4c560969eae..8f299d9ac0c 100644 --- a/lightning/src/routing/router.rs +++ b/lightning/src/routing/router.rs @@ -1164,12 +1164,7 @@ impl cmp::PartialOrd for RouteGraphNode { // While RouteGraphNode can be laid out with fewer bytes, performance appears to be improved // substantially when it is laid out at exactly 64 bytes. -// -// Thus, we use `#[repr(C)]` on the struct to force a suboptimal layout and check that it stays 64 -// bytes here. -#[cfg(any(ldk_bench, not(any(test, fuzzing))))] const _GRAPH_NODE_SMALL: usize = 64 - core::mem::size_of::(); -#[cfg(any(ldk_bench, not(any(test, fuzzing))))] const _GRAPH_NODE_FIXED_SIZE: usize = core::mem::size_of::() - 64; /// A [`CandidateRouteHop::FirstHop`] entry. @@ -1673,7 +1668,7 @@ fn iter_equal(mut iter_a: I1, mut iter_b: I2) /// Fee values should be updated only in the context of the whole path, see update_value_and_recompute_fees. /// These fee values are useful to choose hops as we traverse the graph "payee-to-payer". #[derive(Clone)] -#[repr(C)] // Force fields to appear in the order we define them. +#[repr(align(128))] struct PathBuildingHop<'a> { candidate: CandidateRouteHop<'a>, /// If we've already processed a node as the best node, we shouldn't process it again. Normally @@ -1694,11 +1689,6 @@ struct PathBuildingHop<'a> { /// channel scoring. path_penalty_msat: u64, - // The last 16 bytes are on the next cache line by default in glibc's malloc. Thus, we should - // only place fields which are not hot there. Luckily, the next three fields are only read if - // we end up on the selected path, and only in the final path layout phase, so we don't care - // too much if reading them is slow. - fee_msat: u64, /// All the fees paid *after* this channel on the way to the destination @@ -1715,17 +1705,8 @@ struct PathBuildingHop<'a> { value_contribution_msat: u64, } -// Checks that the entries in the `find_route` `dist` map fit in (exactly) two standard x86-64 -// cache lines. Sadly, they're not guaranteed to actually lie on a cache line (and in fact, -// generally won't, because at least glibc's malloc will align to a nice, big, round -// boundary...plus 16), but at least it will reduce the amount of data we'll need to load. -// -// Note that these assertions only pass on somewhat recent rustc, and thus are gated on the -// ldk_bench flag. -#[cfg(ldk_bench)] -const _NODE_MAP_SIZE_TWO_CACHE_LINES: usize = 128 - core::mem::size_of::<(NodeId, PathBuildingHop)>(); -#[cfg(ldk_bench)] -const _NODE_MAP_SIZE_EXACTLY_CACHE_LINES: usize = core::mem::size_of::<(NodeId, PathBuildingHop)>() - 128; +const _NODE_MAP_SIZE_TWO_CACHE_LINES: usize = 128 - core::mem::size_of::>(); +const _NODE_MAP_SIZE_EXACTLY_TWO_CACHE_LINES: usize = core::mem::size_of::>() - 128; impl<'a> core::fmt::Debug for PathBuildingHop<'a> { fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {