veekaybee

Systems Performance 2nd edition

See synthesized write-up here

• Do a quick performance check in 60 seconds
• Use a number of different tools available in unix
• Use flamegraphs of the callstack if you have access to them
• Best performance winds are elimiating unnecessary wrok, for example a thread stack in a loop, eliminating bad config
• Mantras: Don't do it (elimiate); do it again (caching); do it less (polling), do it when they're not looking, do it concurrently, do it more cheaply

coolaj86

Chat GPT "DAN" (and other "Jailbreaks")

• https://chat.openai.com/
• Is ChatGPT "DAN" Real? Gonna find out [Part 1]
  (https://www.youtube.com/watch?v=-q8woRG9FrI)
• Part 2: I thought ChatGPT DAN was a hoax, but...
  (https://www.youtube.com/watch?v=rHZRrDu3A2U&lc=UgxfrxX8aK7gnCzkend4AaABAg)

ochaton

> tarantool -l fiber -l clock -e 'fiber.create(function() while true do while clock.time() < fiber.time()+0.1 do end fiber.sleep(0.01) end end)' test.lua
entering the event loop
e:100.011µs p:0.017µs t:99.998µs
e:100.042µs p:0.010µs t:100.035µs
e:100.013µs p:0.015µs t:100.004µs
e:100.005µs p:0.006µs t:99.994µs
e:100.007µs p:0.004µs t:99.996µs
e:100.010µs p:0.009µs t:99.993µs
e:100.012µs p:0.016µs t:100.000µs
e:100.009µs p:0.050µs t:99.999µs

Grinnz

Perl 7 FAQ

last updated 2022-05-26

Is Perl 7 coming?

It is the current plan that this version number will be used for Perl at some point in the future.

When is Perl 7 coming?

koshoi

_G.ls = setmetatable({}, {
  __serialize = function()
    local res = {}

    for _, sp_info in box.space._space:pairs(512, { iterator = "GE" }) do
      local sp   = box.space[sp_info.name]
      local info = {}
      info.name   = tostring(sp.name)
      info.engine = tostring(sp.engine)
      info.len    = tostring(sp:len())

knazarov

#!/usr/bin/env tarantool

local pickle = require('pickle')
local yaml = require('yaml')

function trivec(str)
   str = string.lower(str)

   local vec = ""

sharonovd

--- RSA bindings for Tarantool
--- Carefully adapted from https://github.com/spacewander/lua-resty-rsa

local bit = require "bit"
local band = bit.band
local ffi = require "ffi"
local ffi_new = ffi.new
local ffi_gc = ffi.gc
local ffi_copy = ffi.copy
local ffi_str = ffi.string

R-omk

#!/usr/bin/env tarantool

local CONSOLE_SOCKET_PATH = 'unix/:/var/run/tarantool/tarantool.sock'
local os = require("os")

console = require('console')
console.on_start(function(self)
    local status, reason
    status, reason = pcall(function() require('console').connect(CONSOLE_SOCKET_PATH) end)
    if not status then

RunsFor

worker_processes  8;
error_log  logs/error.log  info;
events {
    worker_connections  4096;
}
http {
    include       mime.types;
    default_type  application/octet-stream;
    access_log off;
    sendfile        on;

shafik

What is the Strict Aliasing Rule and Why do we care?

(OR Type Punning, Undefined Behavior and Alignment, Oh My!)

What is strict aliasing? First we will describe what is aliasing and then we can learn what being strict about it means.

In C and C++ aliasing has to do with what expression types we are allowed to access stored values through. In both C and C++ the standard specifies which expression types are allowed to alias which types. The compiler and optimizer are allowed to assume we follow the aliasing rules strictly, hence the term strict aliasing rule. If we attempt to access a value using a type not allowed it is classified as undefined behavior(UB). Once we have undefined behavior all bets are off, the results of our program are no longer reliable.

Unfortunately with strict aliasing violations, we will often obtain the results we expect, leaving the possibility the a future version of a compiler with a new optimization will break code we th