From 86e501bee2e2fbd0a6b6688e1aae0b11845eea87 Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Wed, 13 Dec 2023 00:53:07 +0000 Subject: [PATCH] simd the success prob --- lightning/src/routing/scoring.rs | 55 +++++++++++++++++++++++++++++++- 1 file changed, 54 insertions(+), 1 deletion(-) diff --git a/lightning/src/routing/scoring.rs b/lightning/src/routing/scoring.rs index ed1daa066..346884910 100644 --- a/lightning/src/routing/scoring.rs +++ b/lightning/src/routing/scoring.rs @@ -1098,8 +1098,51 @@ fn linear_success_probability( (numerator, denominator) } +#[repr(align(16))] +struct AlignedFloats([f32; 4]); + #[inline(always)] -fn nonlinear_success_probability( +#[cfg(target_feature = "sse")] +unsafe fn do_nonlinear_success_probability( + amount_msat: u64, min_liquidity_msat: u64, max_liquidity_msat: u64, capacity_msat: u64, +) -> (f32, f32) { + #[cfg(target_arch = "x86")] + use std::arch::x86::*; + #[cfg(target_arch = "x86_64")] + use std::arch::x86_64::*; + + let min_max_amt_max_msat = _mm_set_ps( + min_liquidity_msat as f32, + max_liquidity_msat as f32, + amount_msat as f32, + max_liquidity_msat as f32, + ); + + let capacity = capacity_msat as f32; + let cap_cap_cap_cap = _mm_set_ps(capacity, capacity, capacity, capacity); + + let min_max_amt_max = _mm_div_ps(min_max_amt_max_msat, cap_cap_cap_cap); + + let mhalf_mhalf_mhalf_mhalf = _mm_set_ps(-0.5f32, -0.5f32, -0.5f32, -0.5f32); + let min_max_amt_max_offset = _mm_add_ps(min_max_amt_max, mhalf_mhalf_mhalf_mhalf); + + let min_max_amt_max_sq = _mm_mul_ps(min_max_amt_max_offset, min_max_amt_max_offset); + let min_max_amt_max_pow = _mm_mul_ps(min_max_amt_max_sq, min_max_amt_max_offset); + + let zero_zero_zero_zero = _mm_set_ps(0.0f32, 0.0f32, 0.0f32, 0.0f32); + let maxamt_maxmin_zero_zero = _mm_hsub_ps(min_max_amt_max_pow, zero_zero_zero_zero); + + let mut maxamt_maxmin_zero_zero_mem = AlignedFloats([0.0; 4]); + _mm_store_ps(&mut maxamt_maxmin_zero_zero_mem.0[0], maxamt_maxmin_zero_zero); + ( + maxamt_maxmin_zero_zero_mem.0[0], + maxamt_maxmin_zero_zero_mem.0[1] + ) +} + +#[inline(always)] +#[cfg(not(target_feature = "sse"))] +unsafe fn do_nonlinear_success_probability( amount_msat: u64, min_liquidity_msat: u64, max_liquidity_msat: u64, capacity_msat: u64, ) -> (f32, f32) { let capacity = capacity_msat as f32; @@ -1122,6 +1165,16 @@ fn nonlinear_success_probability( } +#[inline(always)] +fn nonlinear_success_probability( + amount_msat: u64, min_liquidity_msat: u64, max_liquidity_msat: u64, capacity_msat: u64, +) -> (f32, f32) { + unsafe { do_nonlinear_success_probability( + amount_msat, min_liquidity_msat, max_liquidity_msat, capacity_msat + ) } +} + + /// Given liquidity bounds, calculates the success probability (in the form of a numerator and /// denominator) of an HTLC. This is a key assumption in our scoring models. /// -- 2.39.5