test: add harness for measuring performance

tests/perf_harness.lua

@@ -0,0 +1,122 @@
+vim.fn.mkdir("tests/perf/.env", "p")
+local root = vim.fn.fnamemodify("./tests/perf/.env", ":p")
+
+for _, name in ipairs({ "config", "data", "state", "runtime", "cache" }) do
+  vim.env[("XDG_%s_HOME"):format(name:upper())] = root .. name
+end
+
+vim.opt.runtimepath:prepend(vim.fn.fnamemodify(".", ":p"))
+
+---@module 'oil'
+---@type oil.SetupOpts
+local setup_opts = {
+  -- columns = { "icon", "permissions", "size", "mtime" },
+}
+
+local num_files = 100000
+
+if not vim.uv.fs_stat(string.format("tests/perf/file %d.txt", num_files)) then
+  vim.notify("Creating files")
+  for i = 1, num_files, 1 do
+    local filename = ("tests/perf/file %d.txt"):format(i)
+    local fd = vim.uv.fs_open(filename, "a", 420)
+    assert(fd)
+    vim.uv.fs_close(fd)
+  end
+end
+
+local function wait_for_done(callback)
+  vim.api.nvim_create_autocmd("User", {
+    pattern = "OilEnter",
+    once = true,
+    callback = callback,
+  })
+end
+
+function _G.jit_profile()
+  require("oil").setup(setup_opts)
+  local outfile = "tests/perf/profile.txt"
+  require("jit.p").start("3Fpli1s", outfile)
+  local start = vim.uv.hrtime()
+  require("oil").open("tests/perf")
+
+  wait_for_done(function()
+    local delta = vim.uv.hrtime() - start
+    require("jit.p").stop()
+    print("Elapsed:", delta / 1e6, "ms")
+    vim.cmd.edit({ args = { outfile } })
+  end)
+end
+
+function _G.benchmark(iterations)
+  require("oil").setup(setup_opts)
+  local num_outliers = math.floor(0.1 * iterations)
+  local times = {}
+
+  local run_profile
+  run_profile = function()
+    -- Clear out state
+    vim.cmd.enew()
+    for _, bufnr in ipairs(vim.api.nvim_list_bufs()) do
+      if vim.api.nvim_buf_is_valid(bufnr) and bufnr ~= vim.api.nvim_get_current_buf() then
+        vim.api.nvim_buf_delete(bufnr, { force = true })
+      end
+    end
+
+    local start = vim.uv.hrtime()
+    wait_for_done(function()
+      local delta = vim.uv.hrtime() - start
+      table.insert(times, delta / 1e6)
+      if #times < iterations then
+        vim.schedule(run_profile)
+      else
+        -- Remove the outliers
+        table.sort(times)
+        for _ = 1, num_outliers do
+          table.remove(times, 1)
+          table.remove(times)
+        end
+
+        local total = 0
+        for _, time in ipairs(times) do
+          total = total + time
+        end
+
+        local lines = {
+          table.concat(
+            vim.tbl_map(function(t)
+              return string.format("%dms", math.floor(t))
+            end, times),
+            " "
+          ),
+          string.format("Average: %dms", math.floor(total / #times)),
+        }
+        vim.fn.writefile(lines, "tests/perf/benchmark.txt")
+        vim.cmd.qall()
+      end
+    end)
+    require("oil").open("tests/perf")
+  end
+
+  run_profile()
+end
+
+function _G.flame_profile()
+  if not vim.uv.fs_stat("tests/perf/profile.nvim") then
+    vim
+      .system({ "git", "clone", "https://github.com/stevearc/profile.nvim", "tests/perf/profile.nvim" })
+      :wait()
+  end
+  vim.opt.runtimepath:prepend(vim.fn.fnamemodify("./tests/perf/profile.nvim", ":p"))
+  local profile = require("profile")
+  profile.instrument_autocmds()
+  profile.instrument("oil*")
+
+  require("oil").setup(setup_opts)
+  profile.start()
+  require("oil").open("tests/perf")
+  wait_for_done(function()
+    profile.stop("profile.json")
+    vim.cmd.qall()
+  end)
+end