From 8c763f241f8f0be9d63bc4ce44c23b66c0f2fcfc Mon Sep 17 00:00:00 2001
From: "NGnius (Graham)" <ngniusness@gmail.com>
Date: Thu, 5 Jan 2023 21:35:53 -0500
Subject: [PATCH] Improve SMT heuristic when loading from saved

---
 backend/src/settings/generic/cpu.rs    | 7 +++----
 backend/src/settings/mod.rs            | 1 +
 backend/src/settings/steam_deck/cpu.rs | 5 ++---
 backend/src/settings/unknown/cpu.rs    | 5 ++---
 backend/src/settings/util.rs           | 7 +++++++
 5 files changed, 15 insertions(+), 10 deletions(-)
 create mode 100644 backend/src/settings/util.rs

diff --git a/backend/src/settings/generic/cpu.rs b/backend/src/settings/generic/cpu.rs
index a2fe995..b4bba83 100644
--- a/backend/src/settings/generic/cpu.rs
+++ b/backend/src/settings/generic/cpu.rs
@@ -101,7 +101,7 @@ impl<C: AsMut<Cpu> + AsRef<Cpu> + TCpu + FromGenericCpuInfo> Cpus<C> {
         let (_, can_smt) = Self::system_smt_capabilities();
         let mut result = Vec::with_capacity(other.len());
         let max_cpus = Self::cpu_count();
-        let mut smt_disabled = false;
+        let smt_guess = crate::settings::util::guess_smt(&other) && can_smt;
         for (i, cpu) in other.drain(..).enumerate() {
             // prevent having more CPUs than available
             if let Some(max_cpus) = max_cpus {
@@ -109,8 +109,7 @@ impl<C: AsMut<Cpu> + AsRef<Cpu> + TCpu + FromGenericCpuInfo> Cpus<C> {
                     break;
                 }
             }
-            let mut new_cpu = C::from_json_and_limits(cpu, version, i, limits.clone());
-            smt_disabled &= *new_cpu.online() as usize != i % 2;
+            let new_cpu = C::from_json_and_limits(cpu, version, i, limits.clone());
             result.push(new_cpu);
         }
         if let Some(max_cpus) = max_cpus {
@@ -123,7 +122,7 @@ impl<C: AsMut<Cpu> + AsRef<Cpu> + TCpu + FromGenericCpuInfo> Cpus<C> {
         }
         Self {
             cpus: result,
-            smt: !smt_disabled,
+            smt: smt_guess,
             smt_capable: can_smt,
         }
     }
diff --git a/backend/src/settings/mod.rs b/backend/src/settings/mod.rs
index a24b57e..3541526 100644
--- a/backend/src/settings/mod.rs
+++ b/backend/src/settings/mod.rs
@@ -4,6 +4,7 @@ mod error;
 mod general;
 mod min_max;
 mod traits;
+mod util;
 
 pub mod generic;
 pub mod generic_amd;
diff --git a/backend/src/settings/steam_deck/cpu.rs b/backend/src/settings/steam_deck/cpu.rs
index 7ae9630..83a1909 100644
--- a/backend/src/settings/steam_deck/cpu.rs
+++ b/backend/src/settings/steam_deck/cpu.rs
@@ -120,7 +120,7 @@ impl Cpus {
         let (_, can_smt) = Self::system_smt_capabilities();
         let mut result = Vec::with_capacity(other.len());
         let max_cpus = Self::cpu_count();
-        let mut smt_disabled = false;
+        let smt_guess = crate::settings::util::guess_smt(&other) && can_smt;
         for (i, cpu) in other.drain(..).enumerate() {
             // prevent having more CPUs than available
             if let Some(max_cpus) = max_cpus {
@@ -129,7 +129,6 @@ impl Cpus {
                 }
             }
             let new_cpu = Cpu::from_json(cpu, version, i, oc_limits.cpus.get(i).map(|x| x.to_owned()).unwrap_or_default());
-            smt_disabled &= new_cpu.online as usize != i % 2;
             result.push(new_cpu);
         }
         if let Some(max_cpus) = max_cpus {
@@ -142,7 +141,7 @@ impl Cpus {
         }
         Self {
             cpus: result,
-            smt: !smt_disabled,
+            smt: smt_guess,
             smt_capable: can_smt,
             limits: oc_limits,
             driver_mode: driver,
diff --git a/backend/src/settings/unknown/cpu.rs b/backend/src/settings/unknown/cpu.rs
index 76982f4..909c746 100644
--- a/backend/src/settings/unknown/cpu.rs
+++ b/backend/src/settings/unknown/cpu.rs
@@ -105,7 +105,7 @@ impl Cpus {
         let (_, can_smt) = Self::system_smt_capabilities();
         let mut result = Vec::with_capacity(other.len());
         let max_cpus = Self::cpu_count();
-        let mut smt_disabled = false;
+        let smt_guess = crate::settings::util::guess_smt(&other) && can_smt;
         for (i, cpu) in other.drain(..).enumerate() {
             // prevent having more CPUs than available
             if let Some(max_cpus) = max_cpus {
@@ -114,7 +114,6 @@ impl Cpus {
                 }
             }
             let new_cpu = Cpu::from_json(cpu, version, i);
-            smt_disabled &= new_cpu.online as usize != i % 2;
             result.push(new_cpu);
         }
         if let Some(max_cpus) = max_cpus {
@@ -127,7 +126,7 @@ impl Cpus {
         }
         Self {
             cpus: result,
-            smt: !smt_disabled,
+            smt: smt_guess,
             smt_capable: can_smt,
         }
     }
diff --git a/backend/src/settings/util.rs b/backend/src/settings/util.rs
new file mode 100644
index 0000000..83f032d
--- /dev/null
+++ b/backend/src/settings/util.rs
@@ -0,0 +1,7 @@
+pub fn guess_smt(cpus: &Vec<crate::persist::CpuJson>) -> bool {
+    let mut guess = true;
+    for i in (0..cpus.len()).step_by(2) {
+        guess &= cpus[i].online == cpus[i+1].online;
+    }
+    guess
+}