diff --git a/lua/frecency/database.lua b/lua/frecency/database.lua
index d82e62a..e6ff339 100644
--- a/lua/frecency/database.lua
+++ b/lua/frecency/database.lua
@@ -1,11 +1,13 @@
 local Table = require "frecency.database.table"
 local FileLock = require "frecency.file_lock"
+local Timer = require "frecency.timer"
 local config = require "frecency.config"
 local fs = require "frecency.fs"
 local watcher = require "frecency.watcher"
 local log = require "frecency.log"
-local async = require "plenary.async" --[[@as FrecencyPlenaryAsync]]
-local Path = require "plenary.path" --[[@as FrecencyPlenaryPath]]
+local lazy_require = require "frecency.lazy_require"
+local async = lazy_require "plenary.async" --[[@as FrecencyPlenaryAsync]]
+local Path = lazy_require "plenary.path" --[[@as FrecencyPlenaryPath]]
 
 ---@class FrecencyDatabaseEntry
 ---@field ages number[]
@@ -184,7 +186,7 @@ end
 ---@async
 ---@return nil
 function Database:load()
-  local start = os.clock()
+  local timer = Timer.new "load()"
   local err, data = self:file_lock():with(function(target)
     local err, stat = async.uv.fs_stat(target)
     if err then
@@ -203,13 +205,13 @@ function Database:load()
   assert(not err, err)
   local tbl = vim.F.npcall(loadstring(data or ""))
   self.tbl:set(tbl)
-  log.debug(("load() takes %f seconds"):format(os.clock() - start))
+  timer:finish()
 end
 
 ---@async
 ---@return nil
 function Database:save()
-  local start = os.clock()
+  local timer = Timer.new "save()"
   local err = self:file_lock():with(function(target)
     self:raw_save(self.tbl:raw(), target)
     local err, stat = async.uv.fs_stat(target)
@@ -218,7 +220,7 @@ function Database:save()
     return nil
   end)
   assert(not err, err)
-  log.debug(("save() takes %f seconds"):format(os.clock() - start))
+  timer:finish()
 end
 
 ---@async
diff --git a/lua/frecency/database/table.lua b/lua/frecency/database/table.lua
index 8618ca2..a7e41d2 100644
--- a/lua/frecency/database/table.lua
+++ b/lua/frecency/database/table.lua
@@ -1,5 +1,6 @@
-local log = require "frecency.log"
-local async = require "plenary.async"
+local Timer = require "frecency.timer"
+local lazy_require = require "frecency.lazy_require"
+local async = lazy_require "plenary.async" --[[@as FrecencyPlenaryAsync]]
 
 ---@class FrecencyDatabaseRecordValue
 ---@field count integer
@@ -47,13 +48,13 @@ end
 ---@async
 ---@return nil
 function Table:wait_ready()
-  local start = os.clock()
+  local timer = Timer.new "wait_ready()"
   local t = 0.2
   while not rawget(self, "is_ready") do
     async.util.sleep(t)
     t = t * 2
   end
-  log.debug(("wait_ready() takes %f seconds"):format(os.clock() - start))
+  timer:finish()
 end
 
 return Table
diff --git a/lua/frecency/entry_maker.lua b/lua/frecency/entry_maker.lua
index 2fa4af7..17bea10 100644
--- a/lua/frecency/entry_maker.lua
+++ b/lua/frecency/entry_maker.lua
@@ -1,18 +1,18 @@
-local WebDevicons = require "frecency.web_devicons"
+local web_devicons = require "frecency.web_devicons"
 local config = require "frecency.config"
 local fs = require "frecency.fs"
-local Path = require "plenary.path" --[[@as FrecencyPlenaryPath]]
-local entry_display = require "telescope.pickers.entry_display" --[[@as FrecencyTelescopeEntryDisplay]]
-local utils = require "telescope.utils" --[[@as FrecencyTelescopeUtils]]
+local Path = require "plenary.path"
+local lazy_require = require "frecency.lazy_require"
+local entry_display = lazy_require "telescope.pickers.entry_display" --[[@as FrecencyTelescopeEntryDisplay]]
+local utils = lazy_require "telescope.utils" --[[@as FrecencyTelescopeUtils]]
 
 ---@class FrecencyEntryMaker
 ---@field loaded table<string,boolean>
----@field web_devicons WebDevicons
 local EntryMaker = {}
 
 ---@return FrecencyEntryMaker
 EntryMaker.new = function()
-  return setmetatable({ web_devicons = WebDevicons.new() }, { __index = EntryMaker })
+  return setmetatable({}, { __index = EntryMaker })
 end
 
 ---@class FrecencyEntry
@@ -86,7 +86,7 @@ function EntryMaker:width_items(workspace, workspace_tag)
       table.insert(width_items, { width = 6 }) -- fuzzy score
     end
   end
-  if self.web_devicons.is_enabled then
+  if not config.disable_devicons then
     table.insert(width_items, { width = 2 })
   end
   if config.show_filter_column and workspace and workspace_tag then
@@ -116,12 +116,11 @@ function EntryMaker:items(entry, workspace, workspace_tag, formatter)
       table.insert(items, { score, "TelescopeFrecencyScores" })
     end
   end
-  if self.web_devicons.is_enabled then
+  if not config.disable_devicons then
     local basename = utils.path_tail(entry.name)
-    local icon, icon_highlight =
-      self.web_devicons:get_icon(basename, utils.file_extension(basename), { default = false })
+    local icon, icon_highlight = web_devicons.get_icon(basename, utils.file_extension(basename), { default = false })
     if not icon then
-      icon, icon_highlight = self.web_devicons:get_icon(basename, nil, { default = true })
+      icon, icon_highlight = web_devicons.get_icon(basename, nil, { default = true })
     end
     table.insert(items, { icon, icon_highlight })
   end
diff --git a/lua/frecency/file_lock.lua b/lua/frecency/file_lock.lua
index 3c19ac0..a4fbacb 100644
--- a/lua/frecency/file_lock.lua
+++ b/lua/frecency/file_lock.lua
@@ -1,6 +1,7 @@
 local log = require "frecency.log"
-local Path = require "plenary.path" --[[@as FrecencyPlenaryPath]]
-local async = require "plenary.async" --[[@as FrecencyPlenaryAsync]]
+local lazy_require = require "frecency.lazy_require"
+local Path = lazy_require "plenary.path" --[[@as FrecencyPlenaryPath]]
+local async = lazy_require "plenary.async" --[[@as FrecencyPlenaryAsync]]
 
 ---@class FrecencyFileLock
 ---@field base string
diff --git a/lua/frecency/finder.lua b/lua/frecency/finder.lua
index 6bbccc3..d6df044 100644
--- a/lua/frecency/finder.lua
+++ b/lua/frecency/finder.lua
@@ -1,9 +1,12 @@
+local Timer = require "frecency.timer"
 local config = require "frecency.config"
 local fs = require "frecency.fs"
 local os_util = require "frecency.os_util"
+local recency = require "frecency.recency"
 local log = require "frecency.log"
-local Job = require "plenary.job"
-local async = require "plenary.async" --[[@as FrecencyPlenaryAsync]]
+local lazy_require = require "frecency.lazy_require"
+local Job = lazy_require "plenary.job" --[[@as FrecencyPlenaryJob]]
+local async = lazy_require "plenary.async" --[[@as FrecencyPlenaryAsync]]
 
 ---@class FrecencyFinder
 ---@field config FrecencyFinderConfig
@@ -21,7 +24,6 @@ local async = require "plenary.async" --[[@as FrecencyPlenaryAsync]]
 ---@field private need_scan_dir boolean
 ---@field private seen table<string, boolean>
 ---@field private process VimSystemObj?
----@field private recency FrecencyRecency
 ---@field private state FrecencyState
 local Finder = {}
 
@@ -34,11 +36,10 @@ local Finder = {}
 ---@param entry_maker FrecencyEntryMakerInstance
 ---@param need_scandir boolean
 ---@param path string?
----@param recency FrecencyRecency
 ---@param state FrecencyState
 ---@param finder_config? FrecencyFinderConfig
 ---@return FrecencyFinder
-Finder.new = function(database, entry_maker, need_scandir, path, recency, state, finder_config)
+Finder.new = function(database, entry_maker, need_scandir, path, state, finder_config)
   local tx, rx = async.control.channel.mpsc()
   local scan_tx, scan_rx = async.control.channel.mpsc()
   local self = setmetatable({
@@ -47,7 +48,6 @@ Finder.new = function(database, entry_maker, need_scandir, path, recency, state,
     database = database,
     entry_maker = entry_maker,
     path = path,
-    recency = recency,
     state = state,
 
     seen = {},
@@ -257,25 +257,21 @@ end
 ---@return FrecencyFile[]
 function Finder:get_results(workspace, epoch)
   log.debug { workspace = workspace or "NONE" }
-  local start_fetch = os.clock()
+  local timer_fetch = Timer.new "fetching entries"
   local files = self.database:get_entries(workspace, epoch)
-  log.debug(("it takes %f seconds in fetching entries"):format(os.clock() - start_fetch))
-  local start_results = os.clock()
-  local elapsed_recency = 0
+  timer_fetch:finish()
+  local timer_results = Timer.new "making results"
   for _, file in ipairs(files) do
-    local start_recency = os.clock()
-    file.score = file.ages and self.recency:calculate(file.count, file.ages) or 0
+    file.score = file.ages and recency.calculate(file.count, file.ages) or 0
     file.ages = nil
-    elapsed_recency = elapsed_recency + (os.clock() - start_recency)
   end
-  log.debug(("it takes %f seconds in calculating recency"):format(elapsed_recency))
-  log.debug(("it takes %f seconds in making results"):format(os.clock() - start_results))
+  timer_results:finish()
 
-  local start_sort = os.clock()
+  local timer_sort = Timer.new "sorting"
   table.sort(files, function(a, b)
     return a.score > b.score or (a.score == b.score and a.path > b.path)
   end)
-  log.debug(("it takes %f seconds in sorting"):format(os.clock() - start_sort))
+  timer_sort:finish()
   return files
 end
 
diff --git a/lua/frecency/fs.lua b/lua/frecency/fs.lua
index ef57152..6741032 100644
--- a/lua/frecency/fs.lua
+++ b/lua/frecency/fs.lua
@@ -1,11 +1,13 @@
 local config = require "frecency.config"
 local os_util = require "frecency.os_util"
 local log = require "frecency.log"
-local Path = require "plenary.path" --[[@as FrecencyPlenaryPath]]
-local async = require "plenary.async" --[[@as FrecencyPlenaryAsync]]
-local scandir = require "plenary.scandir"
+local lazy_require = require "frecency.lazy_require"
+local Path = lazy_require "plenary.path" --[[@as FrecencyPlenaryPath]]
+local async = lazy_require "plenary.async" --[[@as FrecencyPlenaryAsync]]
+local scandir = lazy_require "plenary.scandir"
 local uv = vim.uv or vim.loop
 
+---@class FrecencyFS
 local M = {
   os_homedir = assert(uv.os_homedir()),
 }
diff --git a/lua/frecency/fuzzy_sorter.lua b/lua/frecency/fuzzy_sorter.lua
index b4db10b..299776c 100644
--- a/lua/frecency/fuzzy_sorter.lua
+++ b/lua/frecency/fuzzy_sorter.lua
@@ -1,5 +1,6 @@
 local config = require "frecency.config"
-local sorters = require "telescope.sorters"
+local lazy_require = require "frecency.lazy_require"
+local sorters = lazy_require "telescope.sorters"
 
 ---@param opts any options for get_fzy_sorter()
 return function(opts)
diff --git a/lua/frecency/init.lua b/lua/frecency/init.lua
index b83d860..b861b44 100644
--- a/lua/frecency/init.lua
+++ b/lua/frecency/init.lua
@@ -5,7 +5,7 @@
 ---@field complete fun(findstart: 1|0, base: string): integer|''|string[]
 ---@field delete async fun(path: string): nil
 ---@field query fun(opts?: FrecencyQueryOpts): FrecencyQueryEntry[]|string[]
----@field register fun(bufnr: integer, datetime: string?): nil
+---@field register async fun(bufnr: integer, datetime: string?): nil
 ---@field start fun(opts: FrecencyPickerOptions?): nil
 ---@field validate_database async fun(force: boolean?): nil
 local frecency = setmetatable({}, {
@@ -43,7 +43,9 @@ local function setup(ext_config)
     return
   end
 
-  require("frecency.config").setup(ext_config)
+  local config = require "frecency.config"
+
+  config.setup(ext_config)
 
   vim.api.nvim_set_hl(0, "TelescopeBufferLoaded", { link = "String", default = true })
   vim.api.nvim_set_hl(0, "TelescopePathSeparator", { link = "Directory", default = true })
@@ -76,9 +78,10 @@ local function setup(ext_config)
         return
       end
       local is_floatwin = vim.api.nvim_win_get_config(0).relative ~= ""
-      if not is_floatwin then
-        frecency.register(args.buf)
+      if is_floatwin or (config.ignore_register and config.ignore_register(args.buf)) then
+        return
       end
+      async_call(frecency.register, args.buf, vim.api.nvim_buf_get_name(args.buf))
     end,
   })
 
diff --git a/lua/frecency/klass.lua b/lua/frecency/klass.lua
index fdfc951..9120b6f 100644
--- a/lua/frecency/klass.lua
+++ b/lua/frecency/klass.lua
@@ -1,54 +1,46 @@
 local Database = require "frecency.database"
-local EntryMaker = require "frecency.entry_maker"
 local Picker = require "frecency.picker"
-local Recency = require "frecency.recency"
+local Timer = require "frecency.timer"
 local config = require "frecency.config"
 local fs = require "frecency.fs"
 local log = require "frecency.log"
-local async = require "plenary.async" --[[@as FrecencyPlenaryAsync]]
+local recency = require "frecency.recency"
+local wait = require "frecency.wait"
+local lazy_require = require "frecency.lazy_require"
+local async = lazy_require "plenary.async" --[[@as FrecencyPlenaryAsync]]
 
 ---@class Frecency
 ---@field private buf_registered table<integer, boolean> flag to indicate the buffer is registered to the database.
 ---@field private database FrecencyDatabase
----@field private entry_maker FrecencyEntryMaker
 ---@field private picker FrecencyPicker
----@field private recency FrecencyRecency
 local Frecency = {}
 
 ---@return Frecency
 Frecency.new = function()
   local self = setmetatable({ buf_registered = {} }, { __index = Frecency }) --[[@as Frecency]]
   self.database = Database.new()
-  self.entry_maker = EntryMaker.new()
-  self.recency = Recency.new()
   return self
 end
 
 ---This is called when `:Telescope frecency` is called at the first time.
 ---@return nil
 function Frecency:setup()
-  local done = false
   ---@async
   local function init()
+    local timer = Timer.new "init()"
     self.database:start()
     self:assert_db_entries()
     if config.auto_validate then
       self:validate_database()
     end
-    done = true
+    timer:finish()
   end
 
   local is_async = not not coroutine.running()
   if is_async then
     init()
   else
-    async.void(init)()
-    local ok, status = vim.wait(10000, function()
-      return done
-    end)
-    if not ok then
-      error("failed to setup:" .. (status == -1 and "timed out" or "interrupted"))
-    end
+    wait(init)
   end
 end
 
@@ -56,7 +48,7 @@ end
 ---@param opts? FrecencyPickerOptions
 ---@return nil
 function Frecency:start(opts)
-  local start = os.clock()
+  local timer = Timer.new "start()"
   log.debug "Frecency:start"
   opts = opts or {}
   if opts.cwd then
@@ -66,13 +58,13 @@ function Frecency:start(opts)
   if opts.hide_current_buffer or config.hide_current_buffer then
     ignore_filenames = { vim.api.nvim_buf_get_name(0) }
   end
-  self.picker = Picker.new(self.database, self.entry_maker, self.recency, {
+  self.picker = Picker.new(self.database, {
     editing_bufnr = vim.api.nvim_get_current_buf(),
     ignore_filenames = ignore_filenames,
     initial_workspace_tag = opts.workspace,
   })
   self.picker:start(vim.tbl_extend("force", config.get(), opts))
-  log.debug(("Frecency:start picker:start takes %f seconds"):format(os.clock() - start))
+  timer:finish()
 end
 
 ---This can be calledBy `require("telescope").extensions.frecency.complete`.
@@ -128,25 +120,21 @@ function Frecency:assert_db_entries()
   end
 end
 
+---@async
 ---@param bufnr integer
+---@param path string
 ---@param epoch? integer
-function Frecency:register(bufnr, epoch)
-  if (config.ignore_register and config.ignore_register(bufnr)) or self.buf_registered[bufnr] then
+function Frecency:register(bufnr, path, epoch)
+  if self.buf_registered[bufnr] or not fs.is_valid_path(path) then
     return
   end
-  local path = vim.api.nvim_buf_get_name(bufnr)
-  async.void(function()
-    if not fs.is_valid_path(path) then
-      return
-    end
-    local err, realpath = async.uv.fs_realpath(path)
-    if err or not realpath then
-      return
-    end
-    self.database:update(realpath, epoch)
-    self.buf_registered[bufnr] = true
-    log.debug("registered:", bufnr, path)
-  end)()
+  local err, realpath = async.uv.fs_realpath(path)
+  if err or not realpath then
+    return
+  end
+  self.database:update(realpath, epoch)
+  self.buf_registered[bufnr] = true
+  log.debug("registered:", bufnr, path)
 end
 
 ---@async
@@ -191,7 +179,7 @@ function Frecency:query(opts, epoch)
     return {
       count = entry.count,
       path = entry.path,
-      score = entry.ages and self.recency:calculate(entry.count, entry.ages) or 0,
+      score = entry.ages and recency.calculate(entry.count, entry.ages) or 0,
       timestamps = entry.timestamps,
     }
   end, self.database:get_entries(opts.workspace, epoch))
diff --git a/lua/frecency/lazy_require.lua b/lua/frecency/lazy_require.lua
new file mode 100644
index 0000000..cf3e333
--- /dev/null
+++ b/lua/frecency/lazy_require.lua
@@ -0,0 +1,11 @@
+---@param module string
+return function(module)
+  return setmetatable({}, {
+    __index = function(_, key)
+      return require(module)[key]
+    end,
+    __call = function(_, ...)
+      return require(module)(...)
+    end,
+  })
+end
diff --git a/lua/frecency/log.lua b/lua/frecency/log.lua
index 6b198d9..61cc91e 100644
--- a/lua/frecency/log.lua
+++ b/lua/frecency/log.lua
@@ -1,8 +1,11 @@
 local config = require "frecency.config"
-local log = require "plenary.log"
+local lazy_require = require "frecency.lazy_require"
+local log = lazy_require "plenary.log"
 
 return setmetatable({}, {
   __index = function(_, key)
-    return config.debug and log[key] or function() end
+    return config.debug and vim.schedule_wrap(function(...)
+      log[key](...)
+    end) or function() end
   end,
 })
diff --git a/lua/frecency/os_util.lua b/lua/frecency/os_util.lua
index bf297de..b8e39e8 100644
--- a/lua/frecency/os_util.lua
+++ b/lua/frecency/os_util.lua
@@ -1,6 +1,8 @@
-local Path = require "plenary.path"
+local lazy_require = require "frecency.lazy_require"
+local Path = lazy_require "plenary.path" --[[@as FrecencyPlenaryPath]]
 local uv = vim.uv or vim.loop
 
+---@class FrecencyOSUtil
 local M = {
   is_windows = uv.os_uname().sysname == "Windows_NT",
 }
diff --git a/lua/frecency/picker.lua b/lua/frecency/picker.lua
index 297b4a5..9cfafda 100644
--- a/lua/frecency/picker.lua
+++ b/lua/frecency/picker.lua
@@ -1,3 +1,4 @@
+local EntryMaker = require "frecency.entry_maker"
 local State = require "frecency.state"
 local Finder = require "frecency.finder"
 local config = require "frecency.config"
@@ -5,11 +6,12 @@ local fs = require "frecency.fs"
 local fuzzy_sorter = require "frecency.fuzzy_sorter"
 local substr_sorter = require "frecency.substr_sorter"
 local log = require "frecency.log"
-local Path = require "plenary.path" --[[@as FrecencyPlenaryPath]]
-local actions = require "telescope.actions"
-local config_values = require("telescope.config").values
-local pickers = require "telescope.pickers"
-local utils = require "telescope.utils" --[[@as FrecencyTelescopeUtils]]
+local lazy_require = require "frecency.lazy_require"
+local Path = lazy_require "plenary.path" --[[@as FrecencyPlenaryPath]]
+local actions = lazy_require "telescope.actions"
+local telescope_config = lazy_require "telescope.config"
+local pickers = lazy_require "telescope.pickers"
+local utils = lazy_require "telescope.utils" --[[@as FrecencyTelescopeUtils]]
 local uv = vim.loop or vim.uv
 
 ---@class FrecencyPicker
@@ -18,7 +20,6 @@ local uv = vim.loop or vim.uv
 ---@field private entry_maker FrecencyEntryMaker
 ---@field private lsp_workspaces string[]
 ---@field private namespace integer
----@field private recency FrecencyRecency
 ---@field private state FrecencyState
 ---@field private workspace string?
 ---@field private workspace_tag_regex string
@@ -37,18 +38,15 @@ local Picker = {}
 ---@field score number
 
 ---@param database FrecencyDatabase
----@param entry_maker FrecencyEntryMaker
----@param recency FrecencyRecency
 ---@param picker_config FrecencyPickerConfig
 ---@return FrecencyPicker
-Picker.new = function(database, entry_maker, recency, picker_config)
+Picker.new = function(database, picker_config)
   local self = setmetatable({
     config = picker_config,
     database = database,
-    entry_maker = entry_maker,
+    entry_maker = EntryMaker.new(),
     lsp_workspaces = {},
     namespace = vim.api.nvim_create_namespace "frecency",
-    recency = recency,
   }, { __index = Picker })
   local d = config.filter_delimiter
   self.workspace_tag_regex = "^%s*" .. d .. "(%S+)" .. d
@@ -80,7 +78,6 @@ function Picker:finder(opts, workspace, workspace_tag)
     entry_maker,
     need_scandir,
     workspace,
-    self.recency,
     self.state,
     { ignore_filenames = self.config.ignore_filenames }
   )
@@ -93,7 +90,7 @@ function Picker:start(opts)
     path_display = function(picker_opts, path)
       return self:default_path_display(picker_opts, path)
     end,
-  }, config_values, opts or {}) --[[@as FrecencyPickerOptions]]
+  }, telescope_config.values, opts or {}) --[[@as FrecencyPickerOptions]]
   self.workspace = self:get_workspace(opts.cwd, self.config.initial_workspace_tag or config.default_workspace)
   log.debug { workspace = self.workspace }
 
@@ -102,7 +99,7 @@ function Picker:start(opts)
   local picker = pickers.new(opts, {
     prompt_title = "Frecency",
     finder = finder,
-    previewer = config_values.file_previewer(opts),
+    previewer = telescope_config.values.file_previewer(opts),
     sorter = config.matcher == "default" and substr_sorter() or fuzzy_sorter(opts),
     on_input_filter_cb = self:on_input_filter_cb(opts),
     attach_mappings = function(prompt_bufnr)
diff --git a/lua/frecency/recency.lua b/lua/frecency/recency.lua
index 8f4edd5..0ed2ea0 100644
--- a/lua/frecency/recency.lua
+++ b/lua/frecency/recency.lua
@@ -1,23 +1,15 @@
 local config = require "frecency.config"
 
 ---@class FrecencyRecency
----@field private modifier table<integer, { age: integer, value: integer }>
-local Recency = {}
-
----@return FrecencyRecency
-Recency.new = function()
-  return setmetatable({
-    modifier = config.recency_values,
-  }, { __index = Recency })
-end
+local M = {}
 
 ---@param count integer
 ---@param ages number[]
 ---@return number
-function Recency:calculate(count, ages)
+function M.calculate(count, ages)
   local score = 0
   for _, age in ipairs(ages) do
-    for _, rank in ipairs(self.modifier) do
+    for _, rank in ipairs(config.recency_values) do
       if age <= rank.age then
         score = score + rank.value
         goto continue
@@ -28,4 +20,4 @@ function Recency:calculate(count, ages)
   return count * score / config.max_timestamps
 end
 
-return Recency
+return M
diff --git a/lua/frecency/substr_sorter.lua b/lua/frecency/substr_sorter.lua
index 205bed0..08502ec 100644
--- a/lua/frecency/substr_sorter.lua
+++ b/lua/frecency/substr_sorter.lua
@@ -1,8 +1,9 @@
 -- TODO: use this module until telescope's release include this below.
 -- https://github.com/nvim-telescope/telescope.nvim/pull/2950
 
-local sorters = require "telescope.sorters"
-local util = require "telescope.utils"
+local lazy_require = require "frecency.lazy_require"
+local sorters = lazy_require "telescope.sorters"
+local util = lazy_require "telescope.utils"
 
 local substr_highlighter = function(make_display)
   return function(_, prompt, display)
diff --git a/lua/frecency/tests/frecency_spec.lua b/lua/frecency/tests/frecency_spec.lua
index 41a807c..31128b3 100644
--- a/lua/frecency/tests/frecency_spec.lua
+++ b/lua/frecency/tests/frecency_spec.lua
@@ -2,6 +2,7 @@
 -- https://github.com/nvim-lua/plenary.nvim/blob/663246936325062427597964d81d30eaa42ab1e4/lua/plenary/test_harness.lua#L86-L86
 vim.opt.runtimepath:append(vim.env.TELESCOPE_PATH)
 
+local Timer = require "frecency.timer"
 local util = require "frecency.tests.util"
 local log = require "plenary.log"
 
@@ -183,7 +184,7 @@ describe("frecency", function()
             register(file, make_epoch "2023-07-29T00:00:00+09:00")
             log.new({}, true)
           end
-          local start = os.clock()
+          local timer = Timer.new "all results"
           local results = vim.tbl_map(function(result)
             result.timestamps = nil
             return result
@@ -191,11 +192,10 @@ describe("frecency", function()
           table.sort(results, function(a, b)
             return a.path < b.path
           end)
-          local elapsed = os.clock() - start
-          log.info(("it takes %f seconds in fetching all results"):format(elapsed))
+          timer:finish()
 
           it("returns appropriate latency (<1.0 second)", function()
-            assert.are.is_true(elapsed < 1.0)
+            assert.are.is_true(timer.elapsed < 1.0)
           end)
 
           it("returns valid response", function()
diff --git a/lua/frecency/tests/recency_spec.lua b/lua/frecency/tests/recency_spec.lua
index 7de6ba6..9c4cd03 100644
--- a/lua/frecency/tests/recency_spec.lua
+++ b/lua/frecency/tests/recency_spec.lua
@@ -1,5 +1,4 @@
-local Recency = require "frecency.recency"
-local recency = Recency.new()
+local recency = require "frecency.recency"
 
 describe("frecency.recency", function()
   for _, c in ipairs {
@@ -13,7 +12,7 @@ describe("frecency.recency", function()
   } do
     local dumped = vim.inspect(c.ages, { indent = "", newline = "" })
     it(("%d, %s => %d"):format(c.count, dumped, c.score), function()
-      assert.are.same(c.score, recency:calculate(c.count, c.ages))
+      assert.are.same(c.score, recency.calculate(c.count, c.ages))
     end)
   end
 end)
diff --git a/lua/frecency/tests/util.lua b/lua/frecency/tests/util.lua
index 933b396..122f246 100644
--- a/lua/frecency/tests/util.lua
+++ b/lua/frecency/tests/util.lua
@@ -7,7 +7,7 @@ local log = require "plenary.log"
 local async = require "plenary.async" --[[@as FrecencyPlenaryAsync]]
 local Path = require "plenary.path"
 local Job = require "plenary.job"
-local wait = require "frecency.tests.wait"
+local wait = require "frecency.wait"
 
 ---@return FrecencyPlenaryPath
 ---@return fun(): nil close swwp all entries
@@ -101,7 +101,7 @@ local function with_files(files, cb_or_config, callback)
     frecency.database:start()
     frecency.database.tbl:wait_ready()
   end)
-  frecency.picker = Picker.new(frecency.database, frecency.entry_maker, frecency.recency, { editing_bufnr = 0 })
+  frecency.picker = Picker.new(frecency.database, { editing_bufnr = 0 })
   local finder = frecency.picker:finder {}
   callback(frecency, finder, dir)
   close()
@@ -116,16 +116,28 @@ end
 ---@return fun(file: string, epoch: integer, reset: boolean?, wipeout?: boolean): nil reset: boolean?): nil
 local function make_register(frecency, dir)
   return function(file, epoch, reset, wipeout)
+    -- NOTE: this function does the same thing as BufWinEnter autocmd.
+    ---@param bufnr integer
+    local function register(bufnr)
+      if vim.api.nvim_buf_get_name(bufnr) == "" then
+        return
+      end
+      local is_floatwin = vim.api.nvim_win_get_config(0).relative ~= ""
+      if is_floatwin or (config.ignore_register and config.ignore_register(bufnr)) then
+        return
+      end
+      async.util.block_on(function()
+        frecency:register(bufnr, vim.api.nvim_buf_get_name(bufnr), epoch)
+      end)
+    end
+
     local path = filepath(dir, file)
     vim.cmd.edit(path)
     local bufnr = assert(vim.fn.bufnr(path))
     if reset then
       frecency.buf_registered[bufnr] = nil
     end
-    frecency:register(bufnr, epoch)
-    vim.wait(1000, function()
-      return not not frecency.buf_registered[bufnr]
-    end)
+    register(bufnr)
     -- HACK: This is needed because almost the same filenames use the same
     -- buffer.
     if wipeout then
@@ -154,7 +166,7 @@ local function with_fake_register(frecency, dir, callback)
     bufnr = bufnr + 1
     buffers[bufnr] = path
     async.util.block_on(function()
-      frecency:register(bufnr, epoch)
+      frecency:register(bufnr, path, epoch)
     end)
   end
   callback(register)
diff --git a/lua/frecency/timer.lua b/lua/frecency/timer.lua
new file mode 100644
index 0000000..ac39ae9
--- /dev/null
+++ b/lua/frecency/timer.lua
@@ -0,0 +1,26 @@
+local config = require "frecency.config"
+local log = require "frecency.log"
+local uv = vim.uv or vim.loop
+
+---@class FrecencyTimer
+---@field elapsed number
+---@field start integer
+---@field title string
+local Timer = {}
+
+---@param title string
+---@return FrecencyTimer
+Timer.new = function(title)
+  return setmetatable({ start = uv.hrtime(), title = title }, { __index = Timer })
+end
+
+---@return nil
+function Timer:finish()
+  if not config.debug then
+    return
+  end
+  self.elapsed = (uv.hrtime() - self.start) / 1000000000
+  log.debug(("[%s] takes %.3f seconds"):format(self.title, self.elapsed))
+end
+
+return Timer
diff --git a/lua/frecency/types.lua b/lua/frecency/types.lua
index 88b9cb2..bd024f8 100644
--- a/lua/frecency/types.lua
+++ b/lua/frecency/types.lua
@@ -2,6 +2,20 @@
 
 -- NOTE: types are borrowed from plenary.nvim
 
+---@class FrecencyPlenaryJob
+---@field new fun(self: FrecencyPlenaryJob, opts: FrecencyPlenaryJobOpts): FrecencyPlenaryJob
+---@field start fun(self: FrecencyPlenaryJob): nil
+---@field handle VimSystemObj uv_process_t
+
+---@class FrecencyPlenaryJobOpts
+---@field cwd? string
+---@field command? string
+---@field args? string[]
+---@field on_stdout? FrecencyPlenaryJobCallback
+---@field on_stderr? FrecencyPlenaryJobCallback
+
+---@alias FrecencyPlenaryJobCallback fun(error: string, data: string, self?: FrecencyPlenaryJob)
+
 ---@class FrecencyPlenaryPath
 ---@field new fun(self: FrecencyPlenaryPath|string, path?: string): FrecencyPlenaryPath
 ---@field absolute fun(): string
diff --git a/lua/frecency/tests/wait.lua b/lua/frecency/wait.lua
similarity index 100%
rename from lua/frecency/tests/wait.lua
rename to lua/frecency/wait.lua
diff --git a/lua/frecency/watcher.lua b/lua/frecency/watcher.lua
index d412580..f838ef6 100644
--- a/lua/frecency/watcher.lua
+++ b/lua/frecency/watcher.lua
@@ -1,19 +1,20 @@
 local log = require "frecency.log"
-local async = require "plenary.async" --[[@as FrecencyPlenaryAsync]]
+local lazy_require = require "frecency.lazy_require"
+local async = lazy_require "plenary.async" --[[@as FrecencyPlenaryAsync]]
 local uv = vim.loop or vim.uv
 
----@class FrecencyNativeWatcherMtime
+---@class FrecencyWatcherMtime
 ---@field sec integer
 ---@field nsec integer
 local Mtime = {}
 
 ---@param mtime FsStatMtime
----@return FrecencyNativeWatcherMtime
+---@return FrecencyWatcherMtime
 Mtime.new = function(mtime)
   return setmetatable({ sec = mtime.sec, nsec = mtime.nsec }, Mtime)
 end
 
----@param other FrecencyNativeWatcherMtime
+---@param other FrecencyWatcherMtime
 ---@return boolean
 function Mtime:__eq(other)
   return self.sec == other.sec and self.nsec == other.nsec
@@ -24,13 +25,13 @@ function Mtime:__tostring()
   return string.format("%d.%d", self.sec, self.nsec)
 end
 
----@class FrecencyNativeWatcher
+---@class FrecencyWatcher
 ---@field handler UvFsEventHandle
 ---@field path string
----@field mtime FrecencyNativeWatcherMtime
+---@field mtime FrecencyWatcherMtime
 local Watcher = {}
 
----@return FrecencyNativeWatcher
+---@return FrecencyWatcher
 Watcher.new = function()
   return setmetatable({ path = "", mtime = Mtime.new { sec = 0, nsec = 0 } }, { __index = Watcher })
 end
diff --git a/lua/frecency/web_devicons.lua b/lua/frecency/web_devicons.lua
index 2cdd1ce..cf1ef69 100644
--- a/lua/frecency/web_devicons.lua
+++ b/lua/frecency/web_devicons.lua
@@ -1,32 +1,14 @@
-local config = require "frecency.config"
+---@class FrecencyWebDevicons
+local M = {
+  ---@param name string?
+  ---@param ext string?
+  ---@param opts table?
+  ---@return string
+  ---@return string
+  get_icon = function(name, ext, opts)
+    local ok, web_devicons = pcall(require, "nvim-web-devicons")
+    return ok and web_devicons.get_icon(name, ext, opts) or "", ""
+  end,
+}
 
----@class WebDeviconsModule
----@field get_icon fun(name?: string, ext?: string, opts?: table): string, string
-
----@class WebDevicons
----@field is_enabled boolean
----@field private web_devicons WebDeviconsModule
-local WebDevicons = {}
-
----@return WebDevicons
-WebDevicons.new = function()
-  local ok, web_devicons = pcall(require, "nvim-web-devicons")
-  return setmetatable(
-    { is_enabled = not config.disable_devicons and ok, web_devicons = web_devicons },
-    { __index = WebDevicons }
-  )
-end
-
----@param name string?
----@param ext string?
----@param opts table?
----@return string
----@return string
-function WebDevicons:get_icon(name, ext, opts)
-  if self.is_enabled then
-    return self.web_devicons.get_icon(name, ext, opts)
-  end
-  return "", ""
-end
-
-return WebDevicons
+return M