diff --git a/src/snmalloc/aal/aal.h b/src/snmalloc/aal/aal.h
index 3bbf63404..6f9ab81fe 100644
--- a/src/snmalloc/aal/aal.h
+++ b/src/snmalloc/aal/aal.h
@@ -9,21 +9,10 @@
 #include "../ds_core/ds_core.h"
 #include "aal_concept.h"
 #include "aal_consts.h"
-
-#if __has_include(<time.h>)
-#  include <time.h>
-#  ifdef CLOCK_MONOTONIC
-#    define SNMALLOC_TICK_USE_CLOCK_GETTIME
-#  endif
-#endif
 #include "snmalloc/stl/utility.h"
 
 #include <stdint.h>
 
-#ifndef SNMALLOC_TICK_USE_CLOCK_GETTIME
-#  include <chrono>
-#endif
-
 #if ( \
   defined(__i386__) || defined(_M_IX86) || defined(_X86_) || \
   defined(__amd64__) || defined(__x86_64__) || defined(_M_X64) || \
@@ -169,37 +158,17 @@ namespace snmalloc
     /**
      * Return an architecture-specific cycle counter.
      *
-     * If the compiler provides a portable prefetch builtin, use it directly,
-     * otherwise delegate to the architecture-specific layer.  This allows new
-     * architectures to avoid needing to implement a custom `tick` method
-     * if they are used only with a compiler that provides the builtin.
+     * If the architecture reports that CPU cycle counters are unavailable,
+     * use any architecture-specific implementation that exists, otherwise
+     * fall back to zero. When counters are available, prefer a compiler
+     * builtin and then the architecture-specific implementation.
      */
     static inline uint64_t tick() noexcept
     {
       if constexpr (
         (Arch::aal_features & NoCpuCycleCounters) == NoCpuCycleCounters)
       {
-#ifdef SNMALLOC_TICK_USE_CLOCK_GETTIME
-        // the buf is populated by clock_gettime
-        SNMALLOC_UNINITIALISED timespec buf;
-        // we can skip the error checking here:
-        // * EFAULT: for out-of-bound pointers (buf is always valid stack
-        // memory)
-        // * EINVAL: for invalid clock_id (we only use CLOCK_MONOTONIC enforced
-        // by POSIX.1)
-        // Notice that clock_gettime is a usually a vDSO call, so the overhead
-        // is minimal.
-        ::clock_gettime(CLOCK_MONOTONIC, &buf);
-        return static_cast<uint64_t>(buf.tv_sec) * 1000'000'000 +
-          static_cast<uint64_t>(buf.tv_nsec);
-#  undef SNMALLOC_TICK_USE_CLOCK_GETTIME
-#else
-        auto tick = std::chrono::high_resolution_clock::now();
-        return static_cast<uint64_t>(
-          std::chrono::duration_cast<std::chrono::nanoseconds>(
-            tick.time_since_epoch())
-            .count());
-#endif
+        return 0;
       }
       else
       {
diff --git a/src/snmalloc/backend_helpers/backend_helpers.h b/src/snmalloc/backend_helpers/backend_helpers.h
index 24e02b053..ee339337b 100644
--- a/src/snmalloc/backend_helpers/backend_helpers.h
+++ b/src/snmalloc/backend_helpers/backend_helpers.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "../mem/mem.h"
 #include "authmap.h"
 #include "buddy.h"
diff --git a/src/snmalloc/ds_aal/ds_aal.h b/src/snmalloc/ds_aal/ds_aal.h
index 21eeb8dd6..e0b4ac202 100644
--- a/src/snmalloc/ds_aal/ds_aal.h
+++ b/src/snmalloc/ds_aal/ds_aal.h
@@ -7,4 +7,5 @@
 #include "../aal/aal.h"
 #include "flaglock.h"
 #include "prevent_fork.h"
+#include "seqset.h"
 #include "singleton.h"
\ No newline at end of file
diff --git a/src/snmalloc/ds_core/seqset.h b/src/snmalloc/ds_aal/seqset.h
similarity index 100%
rename from src/snmalloc/ds_core/seqset.h
rename to src/snmalloc/ds_aal/seqset.h
diff --git a/src/snmalloc/ds_core/cheri.h b/src/snmalloc/ds_core/cheri.h
index db809765c..f10acb4e1 100644
--- a/src/snmalloc/ds_core/cheri.h
+++ b/src/snmalloc/ds_core/cheri.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "mitigations.h"
 
 namespace snmalloc
diff --git a/src/snmalloc/ds_core/ds_core.h b/src/snmalloc/ds_core/ds_core.h
index 38e99dce2..cc395127b 100644
--- a/src/snmalloc/ds_core/ds_core.h
+++ b/src/snmalloc/ds_core/ds_core.h
@@ -15,5 +15,4 @@
 #include "mitigations.h"
 #include "ptrwrap.h"
 #include "redblacktree.h"
-#include "seqset.h"
 #include "tid.h"
\ No newline at end of file
diff --git a/src/snmalloc/global/global.h b/src/snmalloc/global/global.h
index ffa149567..17699ca5a 100644
--- a/src/snmalloc/global/global.h
+++ b/src/snmalloc/global/global.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "bounds_checks.h"
 #include "globalalloc.h"
 #include "libc.h"
diff --git a/src/snmalloc/mem/mem.h b/src/snmalloc/mem/mem.h
index fc5e59965..3e9212635 100644
--- a/src/snmalloc/mem/mem.h
+++ b/src/snmalloc/mem/mem.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "backend_concept.h"
 #include "backend_wrappers.h"
 #include "check_init.h"
diff --git a/src/snmalloc/pal/pal_posix.h b/src/snmalloc/pal/pal_posix.h
index 8feab7ac7..3ab85bf6a 100644
--- a/src/snmalloc/pal/pal_posix.h
+++ b/src/snmalloc/pal/pal_posix.h
@@ -17,6 +17,7 @@
 #include <strings.h>
 #include <sys/mman.h>
 #include <sys/uio.h>
+#include <time.h>
 #include <unistd.h>
 
 #if __has_include(<sys/random.h>)
@@ -404,6 +405,28 @@ namespace snmalloc
         (static_cast<uint64_t>(ts.tv_nsec) / 1000000);
     }
 
+    static uint64_t tick()
+    {
+      if constexpr (
+        (Aal::aal_features & NoCpuCycleCounters) != NoCpuCycleCounters)
+      {
+        return Aal::tick();
+      }
+      else
+      {
+        auto hold = KeepErrno();
+
+        struct timespec ts;
+        if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1)
+        {
+          error("Failed to get monotonic time");
+        }
+
+        return (static_cast<uint64_t>(ts.tv_sec) * 1'000'000'000) +
+          static_cast<uint64_t>(ts.tv_nsec);
+      }
+    }
+
     static uint64_t dev_urandom()
     {
       union
diff --git a/src/snmalloc/pal/pal_windows.h b/src/snmalloc/pal/pal_windows.h
index 15dfaf28e..a44079dea 100644
--- a/src/snmalloc/pal/pal_windows.h
+++ b/src/snmalloc/pal/pal_windows.h
@@ -7,8 +7,8 @@
 #ifdef _WIN32
 #  ifndef _MSC_VER
 #    include <errno.h>
-#    include <stdio.h>
 #  endif
+#  include <cstdio>
 #  ifndef WIN32_LEAN_AND_MEAN
 #    define WIN32_LEAN_AND_MEAN
 #  endif
@@ -309,12 +309,11 @@ namespace snmalloc
       return result;
     }
 
-    static uint64_t internal_time_in_ms()
+    static uint64_t performance_counter_frequency()
     {
-      // Performance counter is a high-precision monotonic clock.
       static stl::Atomic<uint64_t> freq_cache = 0;
-      constexpr uint64_t ms_per_second = 1000;
       SNMALLOC_UNINITIALISED LARGE_INTEGER buf;
+
       auto freq = freq_cache.load(stl::memory_order_relaxed);
       if (SNMALLOC_UNLIKELY(freq == 0))
       {
@@ -324,10 +323,36 @@ namespace snmalloc
         freq = static_cast<uint64_t>(buf.QuadPart);
         freq_cache.store(freq, stl::memory_order_relaxed);
       }
+
+      return freq;
+    }
+
+    static uint64_t internal_time_in_ms()
+    {
+      constexpr uint64_t ms_per_second = 1000;
+      SNMALLOC_UNINITIALISED LARGE_INTEGER buf;
+      auto freq = performance_counter_frequency();
       ::QueryPerformanceCounter(&buf);
       return (static_cast<uint64_t>(buf.QuadPart) * ms_per_second) / freq;
     }
 
+    static uint64_t tick()
+    {
+      if constexpr (
+        (Aal::aal_features & NoCpuCycleCounters) != NoCpuCycleCounters)
+      {
+        return Aal::tick();
+      }
+      else
+      {
+        constexpr uint64_t ns_per_second = 1'000'000'000;
+        SNMALLOC_UNINITIALISED LARGE_INTEGER buf;
+        auto freq = performance_counter_frequency();
+        ::QueryPerformanceCounter(&buf);
+        return (static_cast<uint64_t>(buf.QuadPart) * ns_per_second) / freq;
+      }
+    }
+
 #  ifdef PLATFORM_HAS_WAITONADDRESS
     using WaitingWord = char;
 
diff --git a/src/snmalloc/snmalloc_front.h b/src/snmalloc/snmalloc_front.h
index 4c5aa60ca..f7cedbb4b 100644
--- a/src/snmalloc/snmalloc_front.h
+++ b/src/snmalloc/snmalloc_front.h
@@ -1 +1,3 @@
+#pragma once
+
 #include "global/global.h"
diff --git a/src/snmalloc/stl/cxx/utility.h b/src/snmalloc/stl/cxx/utility.h
index 93ee5df18..b51d9e270 100644
--- a/src/snmalloc/stl/cxx/utility.h
+++ b/src/snmalloc/stl/cxx/utility.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <utility>
 
 namespace snmalloc
diff --git a/src/test/perf/contention/contention.cc b/src/test/perf/contention/contention.cc
index 06a433d43..6bed00545 100644
--- a/src/test/perf/contention/contention.cc
+++ b/src/test/perf/contention/contention.cc
@@ -5,6 +5,7 @@
 
 #include <iomanip>
 #include <iostream>
+#include <snmalloc/pal/pal.h>
 #include <snmalloc/snmalloc.h>
 #include <thread>
 #include <vector>
@@ -30,7 +31,7 @@ class ParallelTest
     auto prev = ready.fetch_add(1);
     if (prev + 1 == cores)
     {
-      start = Aal::tick();
+      start = DefaultPal::tick();
       flag = true;
     }
     while (!flag)
@@ -41,7 +42,7 @@ class ParallelTest
     prev = complete.fetch_add(1);
     if (prev + 1 == cores)
     {
-      end = Aal::tick();
+      end = DefaultPal::tick();
     }
   }
 
diff --git a/src/test/perf/startup/startup.cc b/src/test/perf/startup/startup.cc
index bcfd455f1..dfc6cb0c2 100644
--- a/src/test/perf/startup/startup.cc
+++ b/src/test/perf/startup/startup.cc
@@ -5,6 +5,7 @@
 
 #include <algorithm>
 #include <iostream>
+#include <snmalloc/pal/pal.h>
 #include <snmalloc/snmalloc.h>
 #include <thread>
 #include <vector>
@@ -30,7 +31,7 @@ class ParallelTest
     auto prev = ready.fetch_add(1);
     if (prev + 1 == cores)
     {
-      start = Aal::tick();
+      start = DefaultPal::tick();
       flag = true;
     }
     while (!flag)
@@ -41,7 +42,7 @@ class ParallelTest
     prev = complete.fetch_add(1);
     if (prev + 1 == cores)
     {
-      end = Aal::tick();
+      end = DefaultPal::tick();
     }
   }
 
@@ -76,9 +77,9 @@ int main()
 
   ParallelTest test(
     [](size_t id) {
-      auto start = Aal::tick();
+      auto start = DefaultPal::tick();
       snmalloc::dealloc(snmalloc::alloc(1));
-      auto end = Aal::tick();
+      auto end = DefaultPal::tick();
       counters[id] = end - start;
     },
     nthreads);
diff --git a/src/test/setup.h b/src/test/setup.h
index deb903de6..e18151c5f 100644
--- a/src/test/setup.h
+++ b/src/test/setup.h
@@ -1,3 +1,5 @@
+#pragma once
+
 #if defined(SNMALLOC_CI_BUILD)
 #  include <snmalloc/pal/pal.h>
 #  if defined(WIN32)