Updated Tests::Perf::Timestamps, added scripts/clear.sh

.clang-tidy

@@ -1,3 +1,5 @@
+# See: https://clang.llvm.org/extra/clang-tidy/
+
 Checks: '
 clang-diagnostic-*,
 clang-analyzer-*,
@@ -7,18 +9,17 @@ misc-*,
 modernize-*,
 performance-*,
 portability-*,
-
--cppcoreguidelines-avoid-const-or-ref-data-members
--cppcoreguidelines-avoid-magic-numbers
--cppcoreguidelines-pro-bounds-pointer-arithmetic
--cppcoreguidelines-pro-type-reinterpret-cast
--cppcoreguidelines-special-member-functions
--hicpp-braces-around-statements
--misc-const-correctness
--misc-include-cleaner
--misc-non-private-member-variables-in-classes
--modernize-use-trailing-return-type
--modernize-use-nodiscard
+-cppcoreguidelines-avoid-const-or-ref-data-members,
+-cppcoreguidelines-avoid-magic-numbers,
+-cppcoreguidelines-pro-bounds-pointer-arithmetic,
+-cppcoreguidelines-pro-type-reinterpret-cast,
+-cppcoreguidelines-special-member-functions,
+-hicpp-braces-around-statements,
+-misc-const-correctness,
+-misc-include-cleaner,
+-misc-non-private-member-variables-in-classes,
+-modernize-use-trailing-return-type,
+-modernize-use-nodiscard,
 '
 WarningsAsErrors: '
 clang-diagnostic-*,

README.md

@@ -3,7 +3,7 @@
 [![build](https://github.com/pkarneliuk/dlsm/actions/workflows/ci.yml/badge.svg)](https://github.com/pkarneliuk/dlsm/actions/workflows/ci.yml)
 [![coverage](https://codecov.io/gh/pkarneliuk/dlsm/branch/master/graph/badge.svg)](https://codecov.io/gh/pkarneliuk/dlsm)
 
-## Intruduction
+## Introduction
 This project contains scripts and snippets in C++.
 
 ## Features
@@ -30,3 +30,4 @@ This project contains scripts and snippets in C++.
 
 ## Links and References
  - [Measuring Latency in Linux](http://btorpey.github.io/blog/2014/02/18/clock-sources-in-linux/)
+ - [Weak vs. Strong Memory Models](https://preshing.com/20120930/weak-vs-strong-memory-models/)

include/impl/Signal.hpp

@@ -8,7 +8,7 @@
 
 namespace dlsm::Signal {
 
-enum Type : int {
+enum Type : std::int8_t {
     NONE = 0,
     BUS = SIGBUS,
     INT = SIGINT,

scripts/clear.sh

@@ -0,0 +1,6 @@
+#!/bin/bash -el
+
+Root=$(realpath $(dirname $(realpath $0))/..)
+
+find $Root/build-fedora* -mindepth 1 ! -regex '^.*/.conan2\(/.*\)?' -delete
+find $Root/build-ubuntu* -mindepth 1 ! -regex '^.*/.conan2\(/.*\)?' -delete

src/Signal.cpp

@@ -3,13 +3,15 @@
 #include <cstring>
 #include <format>
 #include <system_error>
+#include <type_traits>
+#include <utility>
 
 namespace dlsm::Signal {
 
 std::string str(const Type signal) {
     const auto description = ::sigdescr_np(signal);
     // C++23 std::to_underlying()
-    if (description == nullptr) return "Unknown signal " + std::to_string(static_cast<int>(signal));
+    if (description == nullptr) return "Unknown signal " + std::to_string(std::underlying_type_t<Type>(signal));
     return description;
 }
 

tests/perf/README.md

@@ -21,6 +21,13 @@ sudo perf stat -e L1-dcache-loads,L1-dcache-load-misses,mem_inst_retired.lock_lo
     --benchmark_enable_random_interleaving=true \
     --benchmark_counters_tabular=true           \
     --benchmark_display_aggregates_only=true
+
+# Watch memory statistics(may affect performance measurements)
+watch -n 0.2 "grep -E Mem\|Huge\|Swap\|Cache\|locked\|Shmem /proc/meminfo && free -hwv"
+# Drop all caches
+sync && echo 3 | sudo tee /proc/sys/vm/drop_caches
+# Virtual Memory statistics measurements interval, default is 1 second
+sudo sysctl vm.stat_interval=300
 ```
 
 ## [delays.py](delays.py)
@@ -39,6 +46,7 @@ numactl --hardware # Display NUMA nodes
 sudo grubby --update-kernel=ALL --args="isolcpus=6-11" # Isolate CPU #6 - #11 from OS scheduling
 sudo grubby --update-kernel=ALL --remove-args="isolcpus=6-11"
 cat /proc/cmdline       # Display kernel startup parameters
+cat /sys/devices/system/cpu/isolated  # display isolated cores
 taskset -c 0,4,6-8 pid  # Setting CPU affinity
 ```
 

tests/perf/Timestamps.hpp

@@ -10,7 +10,7 @@
 
 namespace Tests::Perf {
 
-template <dlsm::Clock::Concept Clock = dlsm::Clock::System, template <typename> typename Allocator = std::allocator>
+template <dlsm::Clock::Concept Clock = dlsm::Clock::Steady, template <typename> typename Allocator = std::allocator>
 struct Timestamps {
     static constexpr std::chrono::nanoseconds Initial{0}, Max{100'000'000};
     static constexpr std::chrono::nanoseconds delta(const std::chrono::nanoseconds& begin,
@@ -26,12 +26,13 @@ struct Timestamps {
     Timestamps(std::size_t lists, std::size_t samples) : lists_{lists, List(samples, Initial)} {}
     List& operator[](std::size_t i) { return lists_.at(i); }
 
-    Timestamps::List delays(const std::size_t master = 0) const {
+    Timestamps::List delays(double skipFirst = 0.0, const std::size_t master = 0) const {
         if (lists_.size() <= 1) return {};
 
         const auto subscribers = lists_.size() - 1;  // - master
         const auto parallel = lists_[0].size() > 100'000;
-        Timestamps::List deltas(subscribers * lists_[0].size(), Initial);
+        const auto skip = static_cast<std::size_t>(double(lists_[0].size()) * (skipFirst / 100.0));
+        Timestamps::List deltas(subscribers * (lists_[0].size() - skip), Initial);
         auto dst = std::begin(deltas);
 
         std::vector<std::future<void>> handles;
@@ -41,15 +42,15 @@ struct Timestamps {
         for (std::size_t s = 0; s < lists_.size(); ++s) {
             if (s == master) continue;
             const auto& sub = lists_[s];  // end samples
-            auto i1 = std::cbegin(pub);
+            auto i1 = std::cbegin(pub) + static_cast<std::ptrdiff_t>(skip);
             auto i2 = std::cend(pub);
-            auto i3 = std::cbegin(sub);
+            auto i3 = std::cbegin(sub) + static_cast<std::ptrdiff_t>(skip);
             if (parallel) {
                 handles.emplace_back(std::async(std::launch::async, [=]() { std::transform(i1, i2, i3, dst, delta); }));
             } else {
                 std::transform(i1, i2, i3, dst, delta);
             }
-            dst += static_cast<long>(pub.size());
+            dst += i2 - i1;
         }
         handles.clear();
         return deltas;
@@ -61,7 +62,9 @@ struct Timestamps {
     };
 
     // Calculate percentiles of delays for all samples
-    std::vector<Percentile> percentiles(const std::size_t master = 0) const { return percentiles(delays(master)); }
+    std::vector<Percentile> percentiles(double skipFirst = 0.0, std::size_t master = 0) const {
+        return percentiles(delays(skipFirst, master));
+    }
 
     static std::vector<Percentile> percentiles(List deltas) {
         if (deltas.empty()) return {};

tests/unit/TestSignal.cpp

@@ -14,7 +14,7 @@ TEST(Signal, Type) {
 
     EXPECT_NO_THROW(dlsm::Signal::send(dlsm::Signal::NONE););
 
-    EXPECT_THAT([] { dlsm::Signal::send(static_cast<dlsm::Signal::Type>(-1)); },
+    EXPECT_THAT([] { dlsm::Signal::send(static_cast<dlsm::Signal::Type>(-1)); },  // NOLINT
                 ThrowsMessage<std::runtime_error>(StartsWith("Signal::send(-1) failed: Invalid argument")));
 }