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@htejun htejun commented Dec 6, 2023

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So that it doesn't cause the missing lifetime parameter warnings everywhere.
@htejun htejun merged commit 291d704 into main Dec 6, 2023
vnepogodin added a commit to CachyOS/scx that referenced this pull request Dec 12, 2024
Into trait was calling the Into<&SupportedSched> which was calling
Into<SupportedSched> and so on.

```
    #0 0x622450e96149 in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#1 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#2 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#3 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#4 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#5 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#6 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#7 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#8 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#9 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#10 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#11 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#12 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#13 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#14 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
```
etsal pushed a commit to etsal/scx that referenced this pull request Dec 16, 2024
Into trait was calling the Into<&SupportedSched> which was calling
Into<SupportedSched> and so on.

```
    #0 0x622450e96149 in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    #1 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    #2 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#3 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#4 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#5 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#6 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#7 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#8 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#9 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#10 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#11 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#12 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
    sched-ext#13 0x622450e91af3 in _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h9481856c4f80c765 /home/vl/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:759:9
    sched-ext#14 0x622450e9614a in scx_loader::_$LT$impl$u20$core..convert..From$LT$scx_loader..SupportedSched$GT$$u20$for$u20$$RF$str$GT$::from::h13ba9d4271e33441 /tmp/scx/rust/scx_loader/src/lib.rs:60:9
```
RitzDaCat added a commit to RitzDaCat/scx that referenced this pull request Nov 26, 2025
…14 bugs)

FIRST SWEEP (7 bugs - Critical dispatch and timing issues):

Bug sched-ext#1-2: SCX_DSQ_LOCAL mismatch and missing CPU kicks
- Problem: Using SCX_DSQ_LOCAL dispatched to calling CPU's DSQ, not target CPU
- Impact: Tasks queued on wrong CPU, causing 50-500µs delays waiting for migration
- Fix: Changed to SCX_DSQ_LOCAL_ON | target_cpu + added scx_bpf_kick_cpu()
- Locations: 15+ fast paths in gamer_select_cpu_slowpath

Bug sched-ext#3: Task slice oscillation (continuous_input_mode hysteresis)
- Problem: Exit threshold (75) too close to entry threshold (100), causing toggling
- Impact: Slice duration oscillated rapidly, causing micro-stutters during input
- Fix: Lowered exit threshold from 75 to 50 for proper hysteresis band

Bug sched-ext#4: hotpath_signals race condition
- Problem: Non-atomic read-then-clear of hotpath_signals.input_ns[]
- Impact: Two CPUs could process same input event (double-dispatch)
- Fix: Used __atomic_exchange_n() for atomic read-and-clear

Bug sched-ext#5: Frame stabilization premature activation
- Problem: Checked frame_stabilization_active before timestamp validity
- Impact: Stale stabilization state from previous frame applied incorrectly
- Fix: Reordered to check timestamp first: now < until && active

Bug sched-ext#6: Integer overflow in dynamic window calculation
- Problem: base << 1 could overflow when base > ULLONG_MAX/2
- Impact: max_window wrapped to tiny value, breaking input boost timing
- Fix: Added explicit overflow check before shift operation

Bug sched-ext#7: Stale idle CPU hint (cache thrashing)
- Problem: IDLE_HINT_VALID_NS was 500µs - too long for gaming workloads
- Impact: Tasks dispatched to CPUs that became busy, causing cache misses
- Fix: Reduced to 100µs for fresher idle hints

SECOND SWEEP (7 bugs - Type safety and more missing kicks):

Bug sched-ext#8: Type mismatch in system_audio_tgids_map lookup (CRITICAL)
- Problem: Cast struct system_audio_entry* to u8*, reading only first byte
- Impact: Audio detection failed when refcount > 255 (byte wrapped to 0)
- Fix: Properly use struct system_audio_entry* and check entry->refcount > 0

Bug sched-ext#9-14: Missing CPU kicks after scx_bpf_test_and_clear_cpu_idle
- Problem: Cleared CPU idle state but didn't kick CPU to run task
- Impact: Tasks waited until next timer tick (1-10ms) instead of immediate wake
- Locations: GPU/compositor path, compiler corral, idle scan loop, taskgraph
- Fix: Added scx_bpf_kick_cpu(candidate, SCX_KICK_IDLE) after each clear

CUMULATIVE IMPACT ANALYSIS:

Before fixes (worst case latency budget per frame at 144Hz = 6.94ms):
- DSQ mismatch: +50-500µs per critical task dispatch
- Missing kicks: +1-10ms waiting for timer tick (devastating)
- Slice oscillation: +100-500µs per slice recalculation
- Race condition: +200-1000µs from double-dispatch confusion
- Stale hints: +50-200µs from cache misses
- Audio detection: Complete audio thread priority loss when refcount > 255
Total potential added latency: 1.4-12.2ms per frame (exceeds frame budget!)

After fixes:
- All fast paths dispatch to correct CPU immediately
- CPU kicks ensure <10µs wakeup latency
- Stable slice durations with proper hysteresis
- Atomic operations prevent race conditions
- Fresh idle hints improve cache locality
- Audio detection works correctly at all refcounts
Expected latency reduction: 90-99% of added jitter eliminated

TESTING RECOMMENDED:
1. High-refresh gaming (144Hz+) - should see more consistent frame times
2. High-polling mouse (1000Hz+) - should feel smoother, less chunky
3. Audio with multiple sources - should maintain priority correctly
4. Sustained input (keyboard held) - should not see slice flickering
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