ioreport: fix CF sample leak; cache mach host port, battery service, SMC key info

IOReportCreateSamples/CreateSamplesDelta return +1-retained CF objects that
were held as UnsafeRawPointer and never released — ~190KB leaked per 2s tick,
~20GB after a couple days of uptime. Release prev sample and delta each cycle.

Also: cache mach_host_self() (send-right refcount leak per call), resolve the
AppleSmartBattery service once instead of registry-matching every tick, cache
SMC key info to halve SMC syscalls, and pre-size the helper's encode buffer.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: abizer

CLAUDE.md

@@ -110,6 +110,10 @@ just release 0.5.0  # → git tag v0.5.0 && git push --tags
 
 **IOReport dlopen:** Dylib at `/usr/lib/libIOReport.dylib`. `IOReportCopyChannelsInGroup` returns immutable → `CFDictionaryCreateMutableCopy` before subscription. Pass `subbedChannels` (not original) to `IOReportCreateSamples`. Iterate via `IOReportIterate` (block-based).
 
+**IOReport Create-rule leaks:** `IOReportCreateSamples` / `IOReportCreateSamplesDelta` return +1-retained CF objects. Held as `UnsafeRawPointer` they're invisible to ARC — must `Unmanaged.fromOpaque(p).release()` both the old prev sample and the delta every tick, or the app leaks ~100KB/sample (20GB after a couple of days).
+
+**Mach port refcounts:** `mach_host_self()` bumps a send-right refcount per call. Cache one `host_t` for the process lifetime instead of calling it every sample.
+
 **IOReport channels:** Use `"CPU Energy"` / `"GPU Energy"` aggregates. For DRAM sum `DRAM*` + `DCS*` + `AMCC*`. For ANE match `ANE*`.
 
 **proc_pidinfo visibility:** `PROC_PIDTASKALLINFO` returns 0 for system processes (uid < 500) without root. Both `PROC_PIDTASKALLINFO` and `PROC_PIDTASKINFO` fail. The helper is required for system process data.

Sources/App/IOReport.swift

@@ -73,9 +73,15 @@ final class IOReportPower: @unchecked Sendable {
     func sample(interval: Double) -> Reading? {
         guard let prev = prevSample else { return nil }
         guard let curr = createSample(subscription, subbedChannels, nil) else { return nil }
-        defer { prevSample = curr }
+        // IOReportCreateSamples/CreateSamplesDelta follow the CF Create rule (+1 retained);
+        // held as UnsafeRawPointer they're invisible to ARC and must be CFReleased here.
+        defer {
+            Unmanaged<AnyObject>.fromOpaque(prev).release()
+            prevSample = curr
+        }
 
         guard let delta = createDelta(prev, curr, nil) else { return nil }
+        defer { Unmanaged<AnyObject>.fromOpaque(delta).release() }
         guard interval > 0.01 else { return nil }
 
         var reading = Reading()

Sources/App/Monitor.swift

@@ -3,6 +3,10 @@ import Darwin
 import IOKit
 import Observation
 
+/// mach_host_self() bumps the port's send-right refcount on every call and the right is
+/// never deallocated here — cache one for the process lifetime instead of leaking refs each tick.
+private let machHost: host_t = mach_host_self()
+
 // MARK: - Models
 
 struct ProcUsage: Identifiable {
@@ -133,7 +137,7 @@ struct SystemInfo {
         var count = mach_msg_type_number_t(MemoryLayout<vm_statistics64>.size / MemoryLayout<integer_t>.size)
         withUnsafeMutablePointer(to: &stats) { ptr in
             ptr.withMemoryRebound(to: integer_t.self, capacity: Int(count)) {
-                _ = host_statistics64(mach_host_self(), HOST_VM_INFO64, $0, &count)
+                _ = host_statistics64(machHost, HOST_VM_INFO64, $0, &count)
             }
         }
         let pageSize = UInt64(vm_kernel_page_size)
@@ -373,14 +377,19 @@ final class SystemMonitor {
 
     // MARK: - Power
 
+    // Cached for the app's lifetime — registry matching every tick is needless IOKit churn
+    private var batteryService: io_service_t = 0
+
     private func samplePower() {
         var reading = PowerReading()
 
-        let service = IOServiceGetMatchingService(
-            kIOMainPortDefault, IOServiceMatching("AppleSmartBattery")
-        )
+        if batteryService == 0 {
+            batteryService = IOServiceGetMatchingService(
+                kIOMainPortDefault, IOServiceMatching("AppleSmartBattery")
+            )
+        }
+        let service = batteryService
         if service != 0 {
-            defer { IOObjectRelease(service) }
             var cfProps: Unmanaged<CFMutableDictionary>?
             if IORegistryEntryCreateCFProperties(service, &cfProps, kCFAllocatorDefault, 0) == kIOReturnSuccess,
                let dict = cfProps?.takeRetainedValue() as? [String: Any] {
@@ -459,7 +468,7 @@ final class SystemMonitor {
         var numInfo: mach_msg_type_number_t = 0
 
         guard host_processor_info(
-            mach_host_self(), PROCESSOR_CPU_LOAD_INFO,
+            machHost, PROCESSOR_CPU_LOAD_INFO,
             &numCPUs, &cpuInfo, &numInfo
         ) == KERN_SUCCESS, let info = cpuInfo else { return }
 

Sources/App/SMC.swift

@@ -45,6 +45,7 @@ final class SMC: @unchecked Sendable {
     )
 
     private var conn: io_connect_t = 0
+    private var keyInfoCache: [UInt32: KeyInfo] = [:]  // key metadata never changes; skip kSMCGetKeyInfo after first read
 
     init?() {
         let service = IOServiceGetMatchingService(
@@ -83,10 +84,15 @@ final class SMC: @unchecked Sendable {
         var inp = Param(), out = Param()
         inp.key = fourCC(key)
 
-        inp.data8 = 9 // kSMCGetKeyInfo
-        guard call(&inp, &out) else { return nil }
+        if let cached = keyInfoCache[inp.key] {
+            inp.keyInfo = cached
+        } else {
+            inp.data8 = 9 // kSMCGetKeyInfo
+            guard call(&inp, &out) else { return nil }
+            keyInfoCache[inp.key] = out.keyInfo
+            inp.keyInfo = out.keyInfo
+        }
 
-        inp.keyInfo = out.keyInfo
         inp.data8 = 5 // kSMCReadKey
         out = Param()
         guard call(&inp, &out) else { return nil }

Sources/Helper/main.swift

@@ -55,6 +55,7 @@ struct ProcessEntry {
 
 func encodeEntries(_ entries: [ProcessEntry]) -> Data {
     var data = Data()
+    data.reserveCapacity(4 + entries.count * 120)  // 46B fixed fields + typical path length
     // Header: entry count
     var count = UInt32(entries.count)
     data.append(Data(bytes: &count, count: 4))