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Merged
Lencerf merged 1 commit into from
Jul 19, 2026
Merged

feat(board): thread-contiguous logical CPU ID mapping #471

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5 changes: 3 additions & 2 deletions alioth-cli/src/boot/boot_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -106,6 +106,7 @@ fn test_parse_args() {
smt: true,
cores: 8,
sockets: 1,
thread_contiguous: false,
},
},
mem: MemSpec {
Expand Down Expand Up @@ -242,7 +243,7 @@ fn test_parse_net_arg(#[case] arg: &str, #[case] want: NetSpec) {
HashMap::from([("id_topo", "cores=8,sockets=2,smt=false")]),
CpuSpec {
count: 16,
topology: CpuTopology { smt: false, cores: 8, sockets: 2 },
topology: CpuTopology { smt: false, cores: 8, sockets: 2, thread_contiguous: false },
}
)]
#[case(
Expand All @@ -251,7 +252,7 @@ fn test_parse_net_arg(#[case] arg: &str, #[case] want: NetSpec) {
HashMap::new(),
CpuSpec {
count: 16,
topology: CpuTopology { smt: false, cores: 16, sockets: 1 }
topology: CpuTopology { smt: false, cores: 16, sockets: 1, thread_contiguous: false }
}
)]
fn test_parse_cpu_arg(
Expand Down
30 changes: 23 additions & 7 deletions alioth/src/board/board.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -84,20 +84,36 @@ pub struct CpuTopology {
#[serde(default)]
/// Number of sockets.
pub sockets: u8,
#[serde(default)]
/// Use thread-contiguous logical CPU ID mapping when SMT is on.
pub thread_contiguous: bool,
}

impl CpuTopology {
pub fn encode(&self, index: u16) -> (u8, u16, u8) {
let total_cores = self.cores * self.sockets as u16;
let thread_id = index / total_cores;
let core_id = index % total_cores % self.cores;
let socket_id = index % total_cores / self.cores;
(socket_id as u8, core_id, thread_id as u8)
if self.thread_contiguous {
let threads_per_core = if self.smt { 2 } else { 1 };
let thread_id = index % threads_per_core;
let core_id = index / threads_per_core % self.cores;
let socket_id = index / threads_per_core / self.cores;
(socket_id as u8, core_id, thread_id as u8)
} else {
let total_cores = self.cores * self.sockets as u16;
let thread_id = index / total_cores;
let core_id = index % total_cores % self.cores;
let socket_id = index % total_cores / self.cores;
(socket_id as u8, core_id, thread_id as u8)
}
}

pub fn decode(&self, socket_id: u8, core_id: u16, thread_id: u8) -> u16 {
let total_cores = self.cores * self.sockets as u16;
thread_id as u16 * total_cores + core_id + socket_id as u16 * self.cores
if self.thread_contiguous {
let threads_per_core = if self.smt { 2 } else { 1 };
(socket_id as u16 * self.cores + core_id) * threads_per_core + thread_id as u16
} else {
let total_cores = self.cores * self.sockets as u16;
thread_id as u16 * total_cores + core_id + socket_id as u16 * self.cores
}
}
}

Expand Down
22 changes: 13 additions & 9 deletions alioth/src/board/board_amd64/board_amd64_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,15 +18,19 @@ use crate::board::CpuTopology;
use crate::board::x86_64::encode_x2apic_id;

#[rstest]
#[case(CpuTopology{smt: false, cores: 1, sockets: 1}, 0, 0)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1}, 0, 0)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1}, 1, 2)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1}, 2, 1)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1}, 3, 3)]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2}, 4, 8)]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2}, 11, 26)]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2}, 14, 5)]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2}, 23, 27)]
#[case(CpuTopology{smt: false, cores: 1, sockets: 1, ..Default::default()}, 0, 0)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: false}, 0, 0)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: false}, 1, 2)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: false}, 2, 1)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: false}, 3, 3)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: true}, 0, 0)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: true}, 1, 1)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: true}, 2, 2)]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: true}, 3, 3)]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: false}, 4, 8)]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: false}, 11, 26)]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: false}, 14, 5)]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: false}, 23, 27)]
fn test_encode_x2apic(#[case] topology: CpuTopology, #[case] index: u16, #[case] x2apic: u32) {
assert_eq!(encode_x2apic_id(&topology, index), x2apic)
}
6 changes: 3 additions & 3 deletions alioth/src/board/board_arm64_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -19,9 +19,9 @@ use crate::board::CpuTopology;
use crate::board::aarch64::encode_mpidr;

#[rstest]
#[case(CpuTopology{smt: false, cores: 1, sockets: 1}, 1, 1)]
#[case(CpuTopology{smt: true, cores: 8, sockets: 1}, 8, 1)]
#[case(CpuTopology{smt: true, cores: 8, sockets: 4}, 45, (1 << 16) | (5 << 8) | 1)]
#[case(CpuTopology{smt: false, cores: 1, sockets: 1, ..Default::default()}, 1, 1)]
#[case(CpuTopology{smt: true, cores: 8, sockets: 1, thread_contiguous: false}, 8, 1)]
#[case(CpuTopology{smt: true, cores: 8, sockets: 4, thread_contiguous: false}, 45, (1 << 16) | (5 << 8) | 1)]
fn test_encode_mpidr(#[case] topology: CpuTopology, #[case] index: u16, #[case] mpidr: u64) {
assert_eq!(encode_mpidr(&topology, index), MpidrEl1(mpidr));
}
28 changes: 19 additions & 9 deletions alioth/src/board/board_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ use crate::board::{CpuSpec, CpuTopology};
smt: false,
cores: 2,
sockets: 1,
..Default::default()
},
}, true)]
#[case(CpuSpec {
Expand All @@ -31,22 +32,31 @@ use crate::board::{CpuSpec, CpuTopology};
smt: true,
cores: 2,
sockets: 1,
..Default::default()
},
}, false)]
fn test_cpu_topology_validate(#[case] spec: CpuSpec, #[case] expected: bool) {
assert_eq!(spec.validate(), expected);
}

#[rstest]
#[case(CpuTopology{smt: false, cores: 1, sockets: 1}, 0, (0, 0, 0))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1}, 0, (0, 0, 0))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1}, 1, (0, 1, 0))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1}, 2, (0, 0, 1))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1}, 3, (0, 1, 1))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2}, 4, (0, 4, 0))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2}, 11, (1, 5, 0))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2}, 14, (0, 2, 1))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2}, 23, (1, 5, 1))]
#[case(CpuTopology{smt: false, cores: 1, sockets: 1, thread_contiguous: false}, 0, (0, 0, 0))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: false}, 0, (0, 0, 0))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: false}, 1, (0, 1, 0))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: false}, 2, (0, 0, 1))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: false}, 3, (0, 1, 1))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: false}, 4, (0, 4, 0))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: false}, 11, (1, 5, 0))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: false}, 14, (0, 2, 1))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: false}, 23, (1, 5, 1))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: true}, 0, (0, 0, 0))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: true}, 1, (0, 0, 1))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: true}, 2, (0, 1, 0))]
#[case(CpuTopology{smt: true, cores: 2, sockets: 1, thread_contiguous: true}, 3, (0, 1, 1))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: true}, 4, (0, 2, 0))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: true}, 11, (0, 5, 1))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: true}, 14, (1, 1, 0))]
#[case(CpuTopology{smt: true, cores: 6, sockets: 2, thread_contiguous: true}, 23, (1, 5, 1))]
fn test_cpu_topology_encode_decode(
#[case] topology: CpuTopology,
#[case] index: u16,
Expand Down