availability numbers, tracing, llvm target abi and features lib problems

.clangd

@@ -16,13 +16,13 @@ CompileFlags:
   # Add: [-std=c23]
   # Add: [-std=c29]
 
-# Core reason for C++17 variant, pair and tuple destructuring, saner template programming
-# Core reason for C++20 concepts for sane template programming, consteval (constexpr bad)
-# Core reason for C++23 stacktraces, std constexpr-ification, consteval, print
-# Core reason for C++26 enum_to_string, string_to_enum, reflection, iostream replacement
-# Core reason for C99   portable static integer sizes
-# Core reason for C11   generic selection, atomic, tls, threads, alignment
-# Core reason for C17   bug fixes and deprecations
-# Core reason for C23   attributes, digit separators ', nullptr, empty initializer, embed
-#                       constexpr to prevent VLA + constant obbject init, auto + generic (without C++ compat)
-# Core reason for C29   relative sane UTF8 conversion
+# Core reasons for C++17 variant, pair and tuple destructuring, saner template programming
+# Core reasons for C++20 concepts for sane template programming, consteval (constexpr bad), format
+# Core reasons for C++23 stacktraces, std constexpr-ification, consteval, print
+# Core reasons for C++26 enum_to_string, string_to_enum, reflection, iostream replacement
+# Core reasons for C99   portable static integer sizes
+# Core reasons for C11   generic selection, atomic, tls, threads, alignment
+# Core reasons for C17   bug fixes and deprecations
+# Core reasons for C23   attributes, digit separators ', nullptr, empty initializer, embed
+#                       constexpr to prevent VLA + constant object init, auto + generic (without C++ compat)
+# Core reasons for C29   relative sane UTF8 conversion

.config/fish/config.fish

@@ -170,8 +170,8 @@ if status is-interactive
   # * zdev/zig-bootstrap/master: CMAKE_GENERATOR=Ninja ./build x86_64-linux-musl native
   #   + enabling checks: -DLLVM_ENABLE_ASSERTIONS=ON \
   #   + preventing oom: -DLLVM_PARALLEL_LINK_JOBS=1 \
-  abbr --add -g  zbdeb ' ./buildrel/stage3/bin/zig build -p deb -Doptimize=Debug --search-prefix "../../zig-bootstrap/master/out/x86_64-linux-musl-native" --zig-lib-dir lib -Dstatic-llvm'
-  abbr --add -g  zdeb ' ../master/rel/bin/zig build -p deb -Doptimize=Debug --search-prefix "../../zig-bootstrap/master/out/x86_64-linux-musl-native" --zig-lib-dir lib -Dstatic-llvm'
+  abbr --add -g  zbdeb ' ./buildrel/stage3/bin/zig build -p deb -Doptimize=Debug --search-prefix "../../zig-bootstrap/master/out/x86_64-linux-musl-native" --zig-lib-dir lib -Dstatic-llvm -Dno-langref'
+  abbr --add -g  zdeb ' ../master/rel/bin/zig build -p deb -Doptimize=Debug --search-prefix "../../zig-bootstrap/master/out/x86_64-linux-musl-native" --zig-lib-dir lib -Dstatic-llvm -Dno-langref'
   abbr --add -g  zbllvm ' CMAKE_GENERATOR=Ninja ./build x86_64-linux-musl native'
   abbr --add -g  zbsrel ' cmake -B buildrel -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH="../../zig-bootstrap/master/out/host/" -GNinja && time cmake --build buildrel -j $(nproc)'
   abbr --add -g  zbrel ' ./buildrel/stage3/bin/zig build -p rel -Doptimize=ReleaseSafe --search-prefix "../../zig-bootstrap/master/out/x86_64-linux-musl-native" --zig-lib-dir lib -Dstatic-llvm -Dno-langref'
@@ -262,6 +262,7 @@ if status is-interactive
   alias schromwlan='firejail --net=wlan0 --private chromium duckduckgo.com'
 
   # rsync
+  # --info=progress2
   abbr --add -g rsync_copy ' rsync -avz --progress -h'
   abbr --add -g rsync_move ' rsync -avz --progress -h --remove-source-files'
   abbr --add -g rsync_update ' rsync -avzu --progress -h'

.config/nvim/lua/my_lint.lua

@@ -19,11 +19,14 @@ if not ok_lint then return end
 -- uv self update
 
 --==tools
+-- uv tool install cppman
 -- uv tool install mypy
 -- uv tool install ruff
 -- uv tool install weasyprint
 -- uv tool install yt-dlp
-
+--
+-- cppman -c -m true -s cppreference.com
+-- man std::thread
 -- idea https://github.com/codex-semantics-library/codex
 
 --==installing pixi

.config/nvim/lua/my_treesitter.lua

@@ -2,6 +2,10 @@
 -- luacheck: globals vim
 -- luacheck: no max line length
 
+-- "Syntax highlighting is a waste of an information channel" by Hill Wayne
+-- tldr; what to highlight should be switchable since colors have high
+-- information density to detect patterns
+
 --====ziggy
 --====config
 

.config/shells/aliases

@@ -220,6 +220,7 @@ alias schromwlan='firejail --net=wlan0 --private chromium duckduckgo.com'
 #mv adapted-preferences.json ~/.config/google-chrome/Default/Preferences
 #
 # rsync
+# --info=progress2
 alias rsync_copy='rsync -avz --progress -h'
 alias rsync_move='rsync -avz --progress -h --remove-source-files'
 alias rsync_update='rsync -avzu --progress -h'
@@ -326,4 +327,4 @@ alias sudo='sudo '
 # Does not work anymore due to #14708
 # zig test exec --zig-lib-dir lib --main-pkg-path lib/std
 # Takes ? minutes.
-# ./deb/bin/zig build test-standalone -Dskip-release -Dskip-non-native
+# ./deb/bin/zig build test-standalone -Dskip-release -Dskip-non-native

templates/ci

@@ -227,5 +227,6 @@ kill (and wait for) parent process (group).
 Observed yesterday on 20240524 Windows in neovim terminal.
 MacOs: process becomes orphaned means it never gets cleaned up
 
-https://lewisgaul.co.uk/blog/coding/2022/05/13/cgroups-intro/
-cgroups overview
+cgroups overview https://lewisgaul.co.uk/blog/coding/2022/05/13/cgroups-intro/
+woodpecker https://woodpecker-ci.org https://github.com/woodpecker-ci/woodpecker go
+forgejo https://forgejo.org/ https://codeberg.org/forgejo/forgejo go

templates/common.cpp

@@ -2847,10 +2847,27 @@ void use_fmt_print();
 void use_fmt_print() {
   std::print(stdout, "Hello, world!\n");
   // std::print(stdout, "%s\n", "Hello, world!"); // %s does not substitute "Hello, world!"
-  std::string s = std::format("The answer is {}.", 42);
-  std::print(stdout, "{}\n", s);
-  (void)s;
-}
+  std::string s1 = std::format("The answer is {}.", 42);
+  std::print(stdout, "{}\n", s1);
+
+  // clangd being showing wrong diagnostics when using c++23
+  // std::vector<int32_t> v1 = {1, 2, 3};
+  // std::string s2 = std::format("The other answer is {}.", v1);
+  // std::print(stdout, "{}\n", s2);
+  // also works for ranges and containers
+  // std::print("{::*^5}", std::vector<int>{1, 2, 3});
+  // std::vector<int> v2 = {1, 2, 3};
+  // std::print("{}\n", v2);
+}
+
+// needs clang 20
+// #include <experimental/scope>
+// void use_scope_exit();
+// void use_scope_exit() {
+//   void *pMem1 = malloc(100);
+//   memcpy(pMem1, "abcdef", 5);
+//   auto guard = std::experimental::scope_exit{[&] { free(pMem1); }};
+// }
 
 void use_string_view();
 void use_string_view() {

templates/common.rs

@@ -9,4 +9,24 @@
 // * often solution is to write macro, so lots of macros pile up and they feel like an entirely
 // different language
 //
-// https://model-checking.github.io/verify-rust-std/
+// https://model-checking.github.io/verify-rust-std/
+
+// SHENNANIGANs
+// * intentionally racy reads and writes (like for parallel seeded region growing) are not
+// expressible currently in Rust
+//   - Function atomic_load_unordered in nightly, do not use this intrinsic as its not in memory model
+//   - Function atomic_store_unordered in nightly, do not use this intrinsic as its not in memory model
+//   - However, according to kprotty "unordered should still be safe to race with"
+// pub struct UnorderedAtomic(UnsafeCell<i32>);
+// impl UnorderedAtomic {
+//     pub fn new() -> Self {
+//         UnorderedAtomic(Default::default())
+//     }
+//     pub fn load(&self) -> i32 {
+//         unsafe { atomic_load_unordered(self.0.get()) }
+//     }
+//     pub fn store(&self, i: i32) {
+//         unsafe { atomic_store_unordered(self.0.get(), i) }
+//     }
+//     unsafe fn raw(&self) -> *mut i32 { self.0.get() }
+// }

templates/common.zig

@@ -25,6 +25,7 @@ const builtin = @import("builtin");
 // rigorous perf - https://github.com/ccurtsinger/stabilizer
 // libtree(ldd as tree) - https://github.com/haampie/libtree
 // typos-cli - https://github.com/crate-ci/typos
+// headless browser - https://github.com/lightpanda-io/browser
 
 // Tools windows
 // raddebugger - https://github.com/EpicGames/raddebugger

templates/distributed_systems

@@ -105,3 +105,16 @@ Network queue implementation without vendor lock-in:
 * develop own QUEUE API
 * provide adapters for  different network work queue protocols
 
+====uptime_downtime
+formula:
+
+uptime       |  downtime       | requirement
+99.00000 %   |  3d 15h 39m     |
+99.90000 %   |      8h 45m 56s | single-region, basic failover
+99.99000 %   |         52m 15s | multi-region, health checks, automatic failover
+99.99900 %   |          5m 15s | every layer redundancy, real-time monitoring, active-active deployment
+99.99990 %   |             31s | chaos engineering, automated canary deployments, sophisticated traffic management
+99.99999 %   |        3.1536ss | likely direct physical connection of limited participants necessary, static routing (estimation)
+99.999999%   |         3*10-1s | soft real-time operating kernel of involved systems (estimation)
+99.9999999%  |         3*10-2s | hard real-time operating kernel of involved systems (estimation)
+99.99999999% |         3*10-3s | hard-ware only (estimation very unclear)

templates/formal_modeling.txt

@@ -46,6 +46,7 @@ https://buttondown.email/hillelwayne/archive/nondeterminism-in-formal-specificat
 ====weak_memory
 * best theory overview and consequences "The One-Decade Task: Putting std::atomic in CUDA. - Olivier Giroux - CppCon 2019"
   https://www.youtube.com/watch?v=VogqOscJYvk
+* only promise theory covers all semantics, but no tooling exists
 * "Multicore Semantics: Making Sense of Relaxed Memory"
 * C/C++
   - sequential
@@ -183,6 +184,7 @@ https://buttondown.email/hillelwayne/archive/nondeterminism-in-formal-specificat
      PNVI-plain, and PVI semantics for C) does not cover all the edge cases from pointers
      https://www.cl.cam.ac.uk/~pes20/cerberus/clarifying-provenance-v4.html#q3.-can-one-make-a-usable-pointer-via-casts-to-intptr_t-and-back
 - 8. build system parallelization relies on "Jobserver Implementation" protocol
+   * only reliable behavior is to close file descriptors and related process owned resources on process termination
    * Pain point: protocol relies on a process manually releasing resources
      before it dies, rather than relying on kernel-managed resources that are
      automatically released when the process dies
@@ -363,7 +365,7 @@ https://buttondown.email/hillelwayne/archive/nondeterminism-in-formal-specificat
   * kv cache etc
   * idea: spikes are like synaptic connection strengths and represent output of neuron
   * spikes express a sequence over time
-- 18. TLA+ as only feasibe system to formally verifiy non-deterministic
+- 18. TLA+ as only feasibe system to formally verify non-deterministic
   parallelism, states and changes over time via temporal logic
   * https://www.learntla.com/
   * TODO

templates/gdb

@@ -295,13 +295,15 @@ if that does not work
 if that does not work
 - debugging inside qemu runner
 if that does not work:
-- reduce the problem + printf debugging of all intermediat artefacts
+- reduce the problem + printf debugging of all intermediate artefacts
   * we have no way to introspect the problem, so we can only try to modify
     the system behavior
 
 gdbserver localhost:2000 ./exec
 target remote localhost:2000
 
+Howto: GDB Remote Serial Protocol Writing a RSP Server Jeremy Bennett Embecosm
+https://www.embecosm.com/appnotes/ean4/embecosm-howto-rsp-server-ean4-issue-2.html#id3074175
 
 -fno-stack-protector
 -static
@@ -373,4 +375,4 @@ Free ones https://zweilosec.gitbook.io/hackers-rest/, https://www.ired.team/
 Manually mapping Windows dll https://www.youtube.com/watch?v=qzZTXcBu3cE
 
 debugger tricks
-* keep line numbers correct (+ while editing) https://nullprogram.com/blog/2024/01/28/
+* keep line numbers correct (+ while editing) https://nullprogram.com/blog/2024/01/28/

templates/linux

@@ -56,6 +56,21 @@ journalctl -n 200
 auditd (access monitoring framework)
 bpftrace (general tracing solution to create + run ebpf programs)
 idea: usage with monitoring, is bcc necessary?
+almost complete tracing solution for Linux, no attaching possible:
+* https://github.com/namhyung/uftrace
+
+====trace
+choices https://www.brendangregg.com/blog/2015-07-08/choosing-a-linux-tracer.html
+
+query trace language for kernel and user space Linux:
+* https://sourceware.org/systemtap/examples/keyword-index.html
+* example https://stackoverflow.com/questions/46783960/systemtap-simple-userspace-example-function-tracing-ubuntu
+* usability issues
+  - SystemTap doesn't (usually) work on kernels newer than the systemtap release due to internal kernel API changes
+  - access to your program state is very painful with bpf
+  - older kernels can't get the kernels headers and debuginfo installed
+  - SystemTap dyninst runtime requires restarting the target so it can LD_PRELOAD
+  - must configure everything like in dtrace https://blogs.oracle.com/linux/post/dtrace-for-the-application-developer-counting-function-calls
 
 cd /sys/kernel/debug/tracing
 echo 'sig==9' > events/signal/signal_generate/filter

templates/llvm

@@ -1,6 +1,22 @@
-Online correctness validation of transformations:
+templates/llvoOnline correctness validation of transformations:
 https://alive2.llvm.org/ce/
 
+Goal: LLVM Design is for a "simple IR" to allow simple and efficient optimizations.
+Problem1: LLVM requires user to handle target features and target abi, which
+is very error-prone; even though to reduce work, having one implementation would
+offset costs.
+Problem2: No way, in general, to retain all the high level information in LLVM without
+flavoring the LLVM IR with target info (C type system and every other lang).
+Solution0: Make it a lib.
+Solution1: Make a (0BSD) target feature library with exhaustive tests.
+Solution2: Make a (0BSD) target abi library with exhaustive tests.
+Problem1.1 and Problem2.1: Design without compromising Goal ("simple IR")?
+-> indirection + callbacks necessary
+-> no fine-tuning feasible without exhaustive tests, logical model, validators
+and formal verification etc
+https://discourse.llvm.org/t/passing-structs-to-c-functions/83938/9
+https://github.com/lifting-bits/anvill
+
 Instructions to bring up cmake and llvm on very old systems with cmake.
 Note: Using `-DLLVM_ENABLE_PROJECTS="all" \` might break, so use minimal necessary output.
 libc and compiler-rt are other common options, but also not necessary.

templates/parallel_programming.txt

@@ -180,3 +180,6 @@ Simple
 * "Simple, Fast, and Practical Non-Blocking and Blocking Concurrent Queue Algorithms" by Maged M. Michael and Michael L. Scott.
   https://github.com/Qarterd/Honeycomb/blob/master/src/common/Honey/Thread/LockFree/Queue.h
   https://www.cs.rochester.edu/research/synchronization/pseudocode/queues.html
+
+"FIFO can be Better than LRU: the Power of Lazy Promotion and Quick Demotion" by Yang et al.
+LP-FIFO (e.g., FIFO-Reinsertion)/CLOCK N’th Chance (2 bits) can be faster, more scalable and have better miss ration than LRU.

templates/tooling

@@ -175,8 +175,11 @@ front-end tools          | perf
 tracing frameworks       | ftrace, perf_event, eBPF
 Back-end instrumentation | tracepoints, kprobes, uprobes
 source: https://wiki.st.com/stm32mpu/wiki/Linux_tracing,_monitoring_and_debugging
+bpf-based
+* https://github.com/grafana/beyla
+* https://github.com/gojue/ecapture https://docs.kubeshark.co/en/encrypted_traffic
 
-Embedded (mutli-partition swapping)
+Embedded (multi-partition swapping)
 https://sbabic.github.io/swupdate/swupdate.html
 
 Non-programming tools:

templates/win

@@ -733,4 +733,9 @@ Tools to inspect Windows registry
 * regdump
 * https://github.com/strozfriedberg/notatin
 * https://github.com/ColinFinck/nt-hive
-* https://github.com/libguestfs/hivex
+* https://github.com/libguestfs/hivex
+
+====trace
+* dtrace
+bcdedit /set dtrace on
+idea: example usage https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/dtrace