diff --git a/src/_pytest/_io/terminalwriter.py b/src/_pytest/_io/terminalwriter.py
index 5db4dc8b6..7bd8507c2 100644
--- a/src/_pytest/_io/terminalwriter.py
+++ b/src/_pytest/_io/terminalwriter.py
@@ -155,7 +155,7 @@ class TerminalWriter:
 
         self.line(line, **kw)
 
-    def write(self, msg: str, **kw: bool) -> None:
+    def write(self, msg: str, *, flush: bool = False, **kw: bool) -> None:
         if msg:
             current_line = msg.rsplit("\n", 1)[-1]
             if "\n" in msg:
@@ -170,12 +170,16 @@ class TerminalWriter:
             else:
                 markupmsg = msg
             self._file.write(markupmsg)
-            self._file.flush()
+            if flush:
+                self.flush()
 
     def line(self, s: str = "", **kw: bool) -> None:
         self.write(s, **kw)
         self.write("\n")
 
+    def flush(self) -> None:
+        self._file.flush()
+
     def _write_source(self, lines: Sequence[str], indents: Sequence[str] = ()) -> None:
         """Write lines of source code possibly highlighted.
 
diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index 2b9bf4f5b..f472354ef 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -1424,7 +1424,7 @@ def _showfixtures_main(config, session):
 
 def write_docstring(tw: TerminalWriter, doc: str, indent: str = "    ") -> None:
     for line in doc.split("\n"):
-        tw.write(indent + line + "\n")
+        tw.line(indent + line)
 
 
 class Function(PyobjMixin, nodes.Item):
diff --git a/src/_pytest/runner.py b/src/_pytest/runner.py
index f87ccb461..76785ada7 100644
--- a/src/_pytest/runner.py
+++ b/src/_pytest/runner.py
@@ -120,6 +120,7 @@ def show_test_item(item):
     used_fixtures = sorted(getattr(item, "fixturenames", []))
     if used_fixtures:
         tw.write(" (fixtures used: {})".format(", ".join(used_fixtures)))
+    tw.flush()
 
 
 def pytest_runtest_setup(item):
diff --git a/src/_pytest/setuponly.py b/src/_pytest/setuponly.py
index aa5a95ff9..c9cc589ff 100644
--- a/src/_pytest/setuponly.py
+++ b/src/_pytest/setuponly.py
@@ -68,6 +68,8 @@ def _show_fixture_action(fixturedef, msg):
     if hasattr(fixturedef, "cached_param"):
         tw.write("[{}]".format(fixturedef.cached_param))
 
+    tw.flush()
+
     if capman:
         capman.resume_global_capture()
 
diff --git a/src/_pytest/terminal.py b/src/_pytest/terminal.py
index 52c04a49c..d46456733 100644
--- a/src/_pytest/terminal.py
+++ b/src/_pytest/terminal.py
@@ -343,7 +343,7 @@ class TerminalReporter:
             fspath = self.startdir.bestrelpath(fspath)
             self._tw.line()
             self._tw.write(fspath + " ")
-        self._tw.write(res, **markup)
+        self._tw.write(res, flush=True, **markup)
 
     def write_ensure_prefix(self, prefix, extra="", **kwargs):
         if self.currentfspath != prefix:
@@ -359,8 +359,11 @@ class TerminalReporter:
             self._tw.line()
             self.currentfspath = None
 
-    def write(self, content, **markup):
-        self._tw.write(content, **markup)
+    def write(self, content: str, *, flush: bool = False, **markup: bool) -> None:
+        self._tw.write(content, flush=flush, **markup)
+
+    def flush(self) -> None:
+        self._tw.flush()
 
     def write_line(self, line, **markup):
         if not isinstance(line, str):
@@ -437,9 +440,11 @@ class TerminalReporter:
         if self.showlongtestinfo:
             line = self._locationline(nodeid, *location)
             self.write_ensure_prefix(line, "")
+            self.flush()
         elif self.showfspath:
             fsid = nodeid.split("::")[0]
             self.write_fspath_result(fsid, "")
+            self.flush()
 
     def pytest_runtest_logreport(self, report: TestReport) -> None:
         self._tests_ran = True
@@ -491,6 +496,7 @@ class TerminalReporter:
                 self._tw.write(word, **markup)
                 self._tw.write(" " + line)
                 self.currentfspath = -2
+        self.flush()
 
     @property
     def _is_last_item(self):
@@ -539,7 +545,7 @@ class TerminalReporter:
         msg = self._get_progress_information_message()
         w = self._width_of_current_line
         fill = self._tw.fullwidth - w - 1
-        self.write(msg.rjust(fill), **{color: True})
+        self.write(msg.rjust(fill), flush=True, **{color: True})
 
     @property
     def _width_of_current_line(self):
@@ -553,10 +559,10 @@ class TerminalReporter:
     def pytest_collection(self) -> None:
         if self.isatty:
             if self.config.option.verbose >= 0:
-                self.write("collecting ... ", bold=True)
+                self.write("collecting ... ", flush=True, bold=True)
                 self._collect_report_last_write = time.time()
         elif self.config.option.verbose >= 1:
-            self.write("collecting ... ", bold=True)
+            self.write("collecting ... ", flush=True, bold=True)
 
     def pytest_collectreport(self, report: CollectReport) -> None:
         if report.failed: