fixup! add benchmark

test/benchmark/treesitter_spec.lua

@@ -3,6 +3,8 @@ local helpers = require('test.functional.helpers')(after_each)
 local clear = helpers.clear
 local exec_lua = helpers.exec_lua
 
+local big_linux_file_url = 'https://raw.githubusercontent.com/torvalds/linux/master/drivers/gpu/drm/amd/include/asic_reg/dcn/dcn_3_2_0_sh_mask.h'
+
 describe('treesitter perf', function()
   setup(function()
     clear()
@@ -47,4 +49,69 @@ describe('treesitter perf', function()
       return vim.uv.hrtime() - start
     ]]
   end)
+
+  -- takes around 2 minutes
+  it('iter_matches', function()
+    local filename = vim.fs.basename(big_linux_file_url)
+
+    if not vim.uv.fs_stat(filename) then
+      helpers.repeated_read_cmd('wget', big_linux_file_url)
+    end
+    helpers.command('edit '..filename)
+
+    --- @param samples integer[]
+    --- @param matches integer
+    local function compute(samples, matches)
+      local sum = 0
+      local sumsq = 0
+      local min = math.huge
+      local max = 0
+      local n = #samples
+      for i = 1, n  do
+        local sample = samples[i]
+        sum = sum + sample
+        sumsq = sumsq + (sample * sample)
+        if sample > max then
+          max = sample
+        end
+        if sample < min then
+          min = sample
+        end
+      end
+
+      local mean = sum / n
+      local sqsum = sum * sum
+      local std = math.sqrt((sumsq - (sqsum / n)) / (n - 1))
+
+      return string.format('N=%d, matches=%d mean=%f, std=%f, min=%f, max=%f', n, matches/n, mean, std, min, max)
+    end
+
+    local result = exec_lua[[
+      local tree = vim.treesitter.get_parser(0, 'c', {})
+      local query = vim.treesitter.query.get('c', 'highlights')
+      tree:parse(true)
+
+      local samples = {} --- @type integer[]
+      local matches = 0
+
+      for i = 1, 10 do
+        local start = vim.uv.hrtime()
+
+        tree:for_each_tree(function(tstree)
+          local root = tstree:root()
+          for _ in query:iter_matches(root, 0) do
+            matches = matches + 1
+          end
+        end)
+
+        local elapsed = vim.uv.hrtime() - start
+        samples[i] = elapsed / 1000000
+      end
+
+      return {samples, matches}
+    ]]
+
+    print(compute(result[1], result[2]))
+  end)
+
 end)