Re: [PATCH v2 03/20] rv/rvgen: replace % string formatting with f-strings

[Wander Lairson Costa <wander@redhat.com>]

On Thu, Feb 05, 2026 at 12:37:13PM +0100, Gabriele Monaco wrote:
> On Wed, 2026-02-04 at 11:42 -0300, Wander Lairson Costa wrote:
> > Replace all instances of percent-style string formatting with
> > f-strings across the rvgen codebase. This modernizes the string
> > formatting to use Python 3.6+ features, providing clearer and more
> > maintainable code while improving runtime performance.
> > 
> > The conversion handles all formatting cases including simple variable
> > substitution, multi-variable formatting, and complex format specifiers.
> > Dynamic width formatting is converted from "%*s" to "{var:>{width}}"
> > using proper alignment syntax. Template strings for generated C code
> > properly escape braces using double-brace syntax to produce literal
> > braces in the output.
> > 
> > F-strings provide approximately 2x performance improvement over percent
> > formatting and are the recommended approach in modern Python.
> > 
> > Signed-off-by: Wander Lairson Costa <wander@redhat.com>
> > Reviewed-by: Nam Cao <namcao@linutronix.de>
> > Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
> > ---
> 
> There's a new one after the rebase, you may want to add this hunk:
> 
> diff --git a/tools/verification/rvgen/rvgen/dot2k.py
> b/tools/verification/rvgen/rvgen/dot2k.py
> index 4bf0db52e626..0d2cdfdf25eb 100644
> --- a/tools/verification/rvgen/rvgen/dot2k.py
> +++ b/tools/verification/rvgen/rvgen/dot2k.py
> @@ -66,7 +66,7 @@ class dot2k(Monitor, Dot2c):
>          buff.append(" *   Documentation/trace/rv/deterministic_automata.rst")
>          buff.append(" */")
>          buff.append("")
> -        buff.append("#define MONITOR_NAME %s" % (self.name))
> +        buff.append(f"#define MONITOR_NAME {self.name}")
>          buff.append("")
>  
>          return buff

Ah, thanks! I will update the patch.

> 
> ---
> 
> Thanks,
> Gabriele
> 
> >  tools/verification/rvgen/__main__.py        |  6 +--
> >  tools/verification/rvgen/rvgen/automata.py  |  6 +--
> >  tools/verification/rvgen/rvgen/dot2c.py     | 38 ++++++-------
> >  tools/verification/rvgen/rvgen/dot2k.py     | 26 ++++-----
> >  tools/verification/rvgen/rvgen/generator.py | 59 ++++++++++-----------
> >  tools/verification/rvgen/rvgen/ltl2k.py     | 30 +++++------
> >  6 files changed, 81 insertions(+), 84 deletions(-)
> > 
> > diff --git a/tools/verification/rvgen/__main__.py
> > b/tools/verification/rvgen/__main__.py
> > index 3bd438f8476ed..50b7d4227fb16 100644
> > --- a/tools/verification/rvgen/__main__.py
> > +++ b/tools/verification/rvgen/__main__.py
> > @@ -45,7 +45,7 @@ if __name__ == '__main__':
> >  
> >      try:
> >          if params.subcmd == "monitor":
> > -            print("Opening and parsing the specification file %s" %
> > params.spec)
> > +            print(f"Opening and parsing the specification file
> > {params.spec}")
> >              if params.monitor_class == "da":
> >                  monitor = dot2k(params.spec, params.monitor_type,
> > vars(params))
> >              elif params.monitor_class == "ltl":
> > @@ -59,11 +59,11 @@ if __name__ == '__main__':
> >          print(f"There was an error processing {params.spec}: {e}",
> > file=sys.stderr)
> >          sys.exit(1)
> >  
> > -    print("Writing the monitor into the directory %s" % monitor.name)
> > +    print(f"Writing the monitor into the directory {monitor.name}")
> >      monitor.print_files()
> >      print("Almost done, checklist")
> >      if params.subcmd == "monitor":
> > -        print("  - Edit the %s/%s.c to add the instrumentation" %
> > (monitor.name, monitor.name))
> > +        print(f"  - Edit the {monitor.name}/{monitor.name}.c to add the
> > instrumentation")
> >          print(monitor.fill_tracepoint_tooltip())
> >      print(monitor.fill_makefile_tooltip())
> >      print(monitor.fill_kconfig_tooltip())
> > diff --git a/tools/verification/rvgen/rvgen/automata.py
> > b/tools/verification/rvgen/rvgen/automata.py
> > index 6ecd5ccd8f3d3..bd8c04526be3a 100644
> > --- a/tools/verification/rvgen/rvgen/automata.py
> > +++ b/tools/verification/rvgen/rvgen/automata.py
> > @@ -39,11 +39,11 @@ class Automata:
> >          basename = ntpath.basename(self.__dot_path)
> >          if not basename.endswith(".dot") and not basename.endswith(".gv"):
> >              print("not a dot file")
> > -            raise AutomataError("not a dot file: %s" % self.__dot_path)
> > +            raise AutomataError(f"not a dot file: {self.__dot_path}")
> >  
> >          model_name = ntpath.splitext(basename)[0]
> >          if model_name.__len__() == 0:
> > -            raise AutomataError("not a dot file: %s" % self.__dot_path)
> > +            raise AutomataError(f"not a dot file: {self.__dot_path}")
> >  
> >          return model_name
> >  
> > @@ -62,7 +62,7 @@ class Automata:
> >          line = dot_lines[cursor].split()
> >  
> >          if (line[0] != "digraph") and (line[1] != "state_automaton"):
> > -            raise AutomataError("Not a valid .dot format: %s" %
> > self.__dot_path)
> > +            raise AutomataError(f"Not a valid .dot format:
> > {self.__dot_path}")
> >          else:
> >              cursor += 1
> >          return dot_lines
> > diff --git a/tools/verification/rvgen/rvgen/dot2c.py
> > b/tools/verification/rvgen/rvgen/dot2c.py
> > index 74147ae2942f9..6a2ad4fbf7824 100644
> > --- a/tools/verification/rvgen/rvgen/dot2c.py
> > +++ b/tools/verification/rvgen/rvgen/dot2c.py
> > @@ -28,17 +28,17 @@ class Dot2c(Automata):
> >  
> >      def __get_enum_states_content(self) -> list[str]:
> >          buff = []
> > -        buff.append("\t%s%s," % (self.initial_state, self.enum_suffix))
> > +        buff.append(f"\t{self.initial_state}{self.enum_suffix},")
> >          for state in self.states:
> >              if state != self.initial_state:
> > -                buff.append("\t%s%s," % (state, self.enum_suffix))
> > -        buff.append("\tstate_max%s," % (self.enum_suffix))
> > +                buff.append(f"\t{state}{self.enum_suffix},")
> > +        buff.append(f"\tstate_max{self.enum_suffix},")
> >  
> >          return buff
> >  
> >      def format_states_enum(self) -> list[str]:
> >          buff = []
> > -        buff.append("enum %s {" % self.enum_states_def)
> > +        buff.append(f"enum {self.enum_states_def} {{")
> >          buff += self.__get_enum_states_content()
> >          buff.append("};\n")
> >  
> > @@ -47,15 +47,15 @@ class Dot2c(Automata):
> >      def __get_enum_events_content(self) -> list[str]:
> >          buff = []
> >          for event in self.events:
> > -            buff.append("\t%s%s," % (event, self.enum_suffix))
> > +            buff.append(f"\t{event}{self.enum_suffix},")
> >  
> > -        buff.append("\tevent_max%s," % self.enum_suffix)
> > +        buff.append(f"\tevent_max{self.enum_suffix},")
> >  
> >          return buff
> >  
> >      def format_events_enum(self) -> list[str]:
> >          buff = []
> > -        buff.append("enum %s {" % self.enum_events_def)
> > +        buff.append(f"enum {self.enum_events_def} {{")
> >          buff += self.__get_enum_events_content()
> >          buff.append("};\n")
> >  
> > @@ -71,25 +71,25 @@ class Dot2c(Automata):
> >              min_type = "unsigned int"
> >  
> >          if self.states.__len__() > 1000000:
> > -            raise AutomataError("Too many states: %d" %
> > self.states.__len__())
> > +            raise AutomataError(f"Too many states: {self.states.__len__()}")
> >  
> >          return min_type
> >  
> >      def format_automaton_definition(self) -> list[str]:
> >          min_type = self.get_minimun_type()
> >          buff = []
> > -        buff.append("struct %s {" % self.struct_automaton_def)
> > -        buff.append("\tchar *state_names[state_max%s];" % (self.enum_suffix))
> > -        buff.append("\tchar *event_names[event_max%s];" % (self.enum_suffix))
> > -        buff.append("\t%s function[state_max%s][event_max%s];" % (min_type,
> > self.enum_suffix, self.enum_suffix))
> > -        buff.append("\t%s initial_state;" % min_type)
> > -        buff.append("\tbool final_states[state_max%s];" % (self.enum_suffix))
> > +        buff.append(f"struct {self.struct_automaton_def} {{")
> > +        buff.append(f"\tchar *state_names[state_max{self.enum_suffix}];")
> > +        buff.append(f"\tchar *event_names[event_max{self.enum_suffix}];")
> > +        buff.append(f"\t{min_type}
> > function[state_max{self.enum_suffix}][event_max{self.enum_suffix}];")
> > +        buff.append(f"\t{min_type} initial_state;")
> > +        buff.append(f"\tbool final_states[state_max{self.enum_suffix}];")
> >          buff.append("};\n")
> >          return buff
> >  
> >      def format_aut_init_header(self) -> list[str]:
> >          buff = []
> > -        buff.append("static const struct %s %s = {" %
> > (self.struct_automaton_def, self.var_automaton_def))
> > +        buff.append(f"static const struct {self.struct_automaton_def}
> > {self.var_automaton_def} = {{")
> >          return buff
> >  
> >      def __get_string_vector_per_line_content(self, entries: list[str]) ->
> > str:
> > @@ -134,9 +134,9 @@ class Dot2c(Automata):
> >                      next_state = self.function[x][y] + self.enum_suffix
> >  
> >                  if linetoolong:
> > -                    line += "\t\t\t%s" % next_state
> > +                    line += f"\t\t\t{next_state}"
> >                  else:
> > -                    line += "%*s" % (maxlen, next_state)
> > +                    line += f"{next_state:>{maxlen}}"
> >                  if y != nr_events-1:
> >                      line += ",\n" if linetoolong else ", "
> >                  else:
> > @@ -180,7 +180,7 @@ class Dot2c(Automata):
> >  
> >      def format_aut_init_final_states(self) -> list[str]:
> >         buff = []
> > -       buff.append("\t.final_states = { %s }," %
> > self.get_aut_init_final_states())
> > +       buff.append(f"\t.final_states = {{ {self.get_aut_init_final_states()}
> > }},")
> >  
> >         return buff
> >  
> > @@ -196,7 +196,7 @@ class Dot2c(Automata):
> >  
> >      def format_invalid_state(self) -> list[str]:
> >          buff = []
> > -        buff.append("#define %s state_max%s\n" % (self.invalid_state_str,
> > self.enum_suffix))
> > +        buff.append(f"#define {self.invalid_state_str}
> > state_max{self.enum_suffix}\n")
> >  
> >          return buff
> >  
> > diff --git a/tools/verification/rvgen/rvgen/dot2k.py
> > b/tools/verification/rvgen/rvgen/dot2k.py
> > index 6128fe2384308..6d4151acc9fe3 100644
> > --- a/tools/verification/rvgen/rvgen/dot2k.py
> > +++ b/tools/verification/rvgen/rvgen/dot2k.py
> > @@ -19,7 +19,7 @@ class dot2k(Monitor, Dot2c):
> >          self.monitor_type = MonitorType
> >          Monitor.__init__(self, extra_params)
> >          Dot2c.__init__(self, file_path, extra_params.get("model_name"))
> > -        self.enum_suffix = "_%s" % self.name
> > +        self.enum_suffix = f"_{self.name}"
> >  
> >      def fill_monitor_type(self) -> str:
> >          return self.monitor_type.upper()
> > @@ -27,7 +27,7 @@ class dot2k(Monitor, Dot2c):
> >      def fill_tracepoint_handlers_skel(self) -> str:
> >          buff = []
> >          for event in self.events:
> > -            buff.append("static void handle_%s(void *data, /* XXX: fill
> > header */)" % event)
> > +            buff.append(f"static void handle_{event}(void *data, /* XXX: fill
> > header */)")
> >              buff.append("{")
> >              handle = "handle_event"
> >              if self.is_start_event(event):
> > @@ -38,9 +38,9 @@ class dot2k(Monitor, Dot2c):
> >                  handle = "handle_start_run_event"
> >              if self.monitor_type == "per_task":
> >                  buff.append("\tstruct task_struct *p = /* XXX: how do I get
> > p? */;");
> > -                buff.append("\tda_%s(p, %s%s);" % (handle, event,
> > self.enum_suffix));
> > +                buff.append(f"\tda_{handle}(p, {event}{self.enum_suffix});");
> >              else:
> > -                buff.append("\tda_%s(%s%s);" % (handle, event,
> > self.enum_suffix));
> > +                buff.append(f"\tda_{handle}({event}{self.enum_suffix});");
> >              buff.append("}")
> >              buff.append("")
> >          return '\n'.join(buff)
> > @@ -48,20 +48,20 @@ class dot2k(Monitor, Dot2c):
> >      def fill_tracepoint_attach_probe(self) -> str:
> >          buff = []
> >          for event in self.events:
> > -            buff.append("\trv_attach_trace_probe(\"%s\", /* XXX: tracepoint
> > */, handle_%s);" % (self.name, event))
> > +            buff.append(f"\trv_attach_trace_probe(\"{self.name}\", /* XXX:
> > tracepoint */, handle_{event});")
> >          return '\n'.join(buff)
> >  
> >      def fill_tracepoint_detach_helper(self) -> str:
> >          buff = []
> >          for event in self.events:
> > -            buff.append("\trv_detach_trace_probe(\"%s\", /* XXX: tracepoint
> > */, handle_%s);" % (self.name, event))
> > +            buff.append(f"\trv_detach_trace_probe(\"{self.name}\", /* XXX:
> > tracepoint */, handle_{event});")
> >          return '\n'.join(buff)
> >  
> >      def fill_model_h_header(self) -> list[str]:
> >          buff = []
> >          buff.append("/* SPDX-License-Identifier: GPL-2.0 */")
> >          buff.append("/*")
> > -        buff.append(" * Automatically generated C representation of %s
> > automaton" % (self.name))
> > +        buff.append(f" * Automatically generated C representation of
> > {self.name} automaton")
> >          buff.append(" * For further information about this format, see kernel
> > documentation:")
> >          buff.append(" *   Documentation/trace/rv/deterministic_automata.rst")
> >          buff.append(" */")
> > @@ -75,10 +75,10 @@ class dot2k(Monitor, Dot2c):
> >          #
> >          # Adjust the definition names
> >          #
> > -        self.enum_states_def = "states_%s" % self.name
> > -        self.enum_events_def = "events_%s" % self.name
> > -        self.struct_automaton_def = "automaton_%s" % self.name
> > -        self.var_automaton_def = "automaton_%s" % self.name
> > +        self.enum_states_def = f"states_{self.name}"
> > +        self.enum_events_def = f"events_{self.name}"
> > +        self.struct_automaton_def = f"automaton_{self.name}"
> > +        self.var_automaton_def = f"automaton_{self.name}"
> >  
> >          buff = self.fill_model_h_header()
> >          buff += self.format_model()
> > @@ -113,8 +113,8 @@ class dot2k(Monitor, Dot2c):
> >              tp_args.insert(0, tp_args_id)
> >          tp_proto_c = ", ".join([a+b for a,b in tp_args])
> >          tp_args_c = ", ".join([b for a,b in tp_args])
> > -        buff.append("	     TP_PROTO(%s)," % tp_proto_c)
> > -        buff.append("	     TP_ARGS(%s)" % tp_args_c)
> > +        buff.append(f"	     TP_PROTO({tp_proto_c}),")
> > +        buff.append(f"	     TP_ARGS({tp_args_c})")
> >          return '\n'.join(buff)
> >  
> >      def fill_main_c(self) -> str:
> > diff --git a/tools/verification/rvgen/rvgen/generator.py
> > b/tools/verification/rvgen/rvgen/generator.py
> > index af1662e2c20a7..6d16fb68798a7 100644
> > --- a/tools/verification/rvgen/rvgen/generator.py
> > +++ b/tools/verification/rvgen/rvgen/generator.py
> > @@ -40,7 +40,7 @@ class RVGenerator:
> >          if platform.system() != "Linux":
> >              raise OSError("I can only run on Linux.")
> >  
> > -        kernel_path = os.path.join("/lib/modules/%s/build" %
> > platform.release(), self.rv_dir)
> > +        kernel_path =
> > os.path.join(f"/lib/modules/{platform.release()}/build", self.rv_dir)
> >  
> >          # if the current kernel is from a distro this may not be a full
> > kernel tree
> >          # verify that one of the files we are going to modify is available
> > @@ -69,11 +69,11 @@ class RVGenerator:
> >              return self._read_file(path)
> >  
> >      def fill_parent(self):
> > -        return "&rv_%s" % self.parent if self.parent else "NULL"
> > +        return f"&rv_{self.parent}" if self.parent else "NULL"
> >  
> >      def fill_include_parent(self):
> >          if self.parent:
> > -            return "#include <monitors/%s/%s.h>\n" % (self.parent,
> > self.parent)
> > +            return f"#include <monitors/{self.parent}/{self.parent}.h>\n"
> >          return ""
> >  
> >      def fill_tracepoint_handlers_skel(self):
> > @@ -119,7 +119,7 @@ class RVGenerator:
> >          buff = []
> >          buff.append("	# XXX: add dependencies if there")
> >          if self.parent:
> > -            buff.append("	depends on RV_MON_%s" % self.parent.upper())
> > +            buff.append(f"	depends on RV_MON_{self.parent.upper()}")
> >              buff.append("	default y")
> >          return '\n'.join(buff)
> >  
> > @@ -145,31 +145,30 @@ class RVGenerator:
> >          monitor_class_type = self.fill_monitor_class_type()
> >          if self.auto_patch:
> >              self._patch_file("rv_trace.h",
> > -                            "// Add new monitors based on CONFIG_%s here" %
> > monitor_class_type,
> > -                            "#include <monitors/%s/%s_trace.h>" % (self.name,
> > self.name))
> > -            return "  - Patching %s/rv_trace.h, double check the result" %
> > self.rv_dir
> > +                            f"// Add new monitors based on
> > CONFIG_{monitor_class_type} here",
> > +                            f"#include
> > <monitors/{self.name}/{self.name}_trace.h>")
> > +            return f"  - Patching {self.rv_dir}/rv_trace.h, double check the
> > result"
> >  
> > -        return """  - Edit %s/rv_trace.h:
> > -Add this line where other tracepoints are included and %s is defined:
> > -#include <monitors/%s/%s_trace.h>
> > -""" % (self.rv_dir, monitor_class_type, self.name, self.name)
> > +        return f"""  - Edit {self.rv_dir}/rv_trace.h:
> > +Add this line where other tracepoints are included and {monitor_class_type}
> > is defined:
> > +#include <monitors/{self.name}/{self.name}_trace.h>
> > +"""
> >  
> >      def _kconfig_marker(self, container=None) -> str:
> > -        return "# Add new %smonitors here" % (container + " "
> > -                                              if container else "")
> > +        return f"# Add new {container + ' ' if container else ''}monitors
> > here"
> >  
> >      def fill_kconfig_tooltip(self):
> >          if self.auto_patch:
> >              # monitors with a container should stay together in the Kconfig
> >              self._patch_file("Kconfig",
> >                               self._kconfig_marker(self.parent),
> > -                            "source \"kernel/trace/rv/monitors/%s/Kconfig\""
> > % (self.name))
> > -            return "  - Patching %s/Kconfig, double check the result" %
> > self.rv_dir
> > +                            f"source
> > \"kernel/trace/rv/monitors/{self.name}/Kconfig\"")
> > +            return f"  - Patching {self.rv_dir}/Kconfig, double check the
> > result"
> >  
> > -        return """  - Edit %s/Kconfig:
> > +        return f"""  - Edit {self.rv_dir}/Kconfig:
> >  Add this line where other monitors are included:
> > -source \"kernel/trace/rv/monitors/%s/Kconfig\"
> > -""" % (self.rv_dir, self.name)
> > +source \"kernel/trace/rv/monitors/{self.name}/Kconfig\"
> > +"""
> >  
> >      def fill_makefile_tooltip(self):
> >          name = self.name
> > @@ -177,18 +176,18 @@ source \"kernel/trace/rv/monitors/%s/Kconfig\"
> >          if self.auto_patch:
> >              self._patch_file("Makefile",
> >                              "# Add new monitors here",
> > -                            "obj-$(CONFIG_RV_MON_%s) += monitors/%s/%s.o" %
> > (name_up, name, name))
> > -            return "  - Patching %s/Makefile, double check the result" %
> > self.rv_dir
> > +                            f"obj-$(CONFIG_RV_MON_{name_up}) +=
> > monitors/{name}/{name}.o")
> > +            return f"  - Patching {self.rv_dir}/Makefile, double check the
> > result"
> >  
> > -        return """  - Edit %s/Makefile:
> > +        return f"""  - Edit {self.rv_dir}/Makefile:
> >  Add this line where other monitors are included:
> > -obj-$(CONFIG_RV_MON_%s) += monitors/%s/%s.o
> > -""" % (self.rv_dir, name_up, name, name)
> > +obj-$(CONFIG_RV_MON_{name_up}) += monitors/{name}/{name}.o
> > +"""
> >  
> >      def fill_monitor_tooltip(self):
> >          if self.auto_patch:
> > -            return "  - Monitor created in %s/monitors/%s" % (self.rv_dir,
> > self. name)
> > -        return "  - Move %s/ to the kernel's monitor directory (%s/monitors)"
> > % (self.name, self.rv_dir)
> > +            return f"  - Monitor created in
> > {self.rv_dir}/monitors/{self.name}"
> > +        return f"  - Move {self.name}/ to the kernel's monitor directory
> > ({self.rv_dir}/monitors)"
> >  
> >      def __create_directory(self):
> >          path = self.name
> > @@ -205,13 +204,13 @@ obj-$(CONFIG_RV_MON_%s) += monitors/%s/%s.o
> >          file.close()
> >  
> >      def _create_file(self, file_name, content):
> > -        path = "%s/%s" % (self.name, file_name)
> > +        path = f"{self.name}/{file_name}"
> >          if self.auto_patch:
> >              path = os.path.join(self.rv_dir, "monitors", path)
> >          self.__write_file(path, content)
> >  
> >      def __get_main_name(self):
> > -        path = "%s/%s" % (self.name, "main.c")
> > +        path = f"{self.name}/main.c"
> >          if not os.path.exists(path):
> >              return "main.c"
> >          return "__main.c"
> > @@ -221,11 +220,11 @@ obj-$(CONFIG_RV_MON_%s) += monitors/%s/%s.o
> >  
> >          self.__create_directory()
> >  
> > -        path = "%s.c" % self.name
> > +        path = f"{self.name}.c"
> >          self._create_file(path, main_c)
> >  
> >          model_h = self.fill_model_h()
> > -        path = "%s.h" % self.name
> > +        path = f"{self.name}.h"
> >          self._create_file(path, model_h)
> >  
> >          kconfig = self.fill_kconfig()
> > @@ -256,5 +255,5 @@ class Monitor(RVGenerator):
> >      def print_files(self):
> >          super().print_files()
> >          trace_h = self.fill_trace_h()
> > -        path = "%s_trace.h" % self.name
> > +        path = f"{self.name}_trace.h"
> >          self._create_file(path, trace_h)
> > diff --git a/tools/verification/rvgen/rvgen/ltl2k.py
> > b/tools/verification/rvgen/rvgen/ltl2k.py
> > index b075f98d50c47..fa9ea6d597095 100644
> > --- a/tools/verification/rvgen/rvgen/ltl2k.py
> > +++ b/tools/verification/rvgen/rvgen/ltl2k.py
> > @@ -73,7 +73,7 @@ class ltl2k(generator.Monitor):
> >          ]
> >  
> >          for node in self.ba:
> > -            buf.append("\tS%i," % node.id)
> > +            buf.append(f"\tS{node.id},")
> >          buf.append("\tRV_NUM_BA_STATES")
> >          buf.append("};")
> >          buf.append("static_assert(RV_NUM_BA_STATES <= RV_MAX_BA_STATES);")
> > @@ -82,7 +82,7 @@ class ltl2k(generator.Monitor):
> >      def _fill_atoms(self):
> >          buf = ["enum ltl_atom {"]
> >          for a in sorted(self.atoms):
> > -            buf.append("\tLTL_%s," % a)
> > +            buf.append(f"\tLTL_{a},")
> >          buf.append("\tLTL_NUM_ATOM")
> >          buf.append("};")
> >          buf.append("static_assert(LTL_NUM_ATOM <= RV_MAX_LTL_ATOM);")
> > @@ -96,7 +96,7 @@ class ltl2k(generator.Monitor):
> >          ]
> >  
> >          for name in self.atoms_abbr:
> > -            buf.append("\t\t\"%s\"," % name)
> > +            buf.append(f"\t\t\"{name}\",")
> >  
> >          buf.extend([
> >              "\t};",
> > @@ -113,19 +113,19 @@ class ltl2k(generator.Monitor):
> >                  continue
> >  
> >              if isinstance(node.op, ltl2ba.AndOp):
> > -                buf.append("\tbool %s = %s && %s;" % (node, node.op.left,
> > node.op.right))
> > +                buf.append(f"\tbool {node} = {node.op.left} &&
> > {node.op.right};")
> >                  required_values |= {str(node.op.left), str(node.op.right)}
> >              elif isinstance(node.op, ltl2ba.OrOp):
> > -                buf.append("\tbool %s = %s || %s;" % (node, node.op.left,
> > node.op.right))
> > +                buf.append(f"\tbool {node} = {node.op.left} ||
> > {node.op.right};")
> >                  required_values |= {str(node.op.left), str(node.op.right)}
> >              elif isinstance(node.op, ltl2ba.NotOp):
> > -                buf.append("\tbool %s = !%s;" % (node, node.op.child))
> > +                buf.append(f"\tbool {node} = !{node.op.child};")
> >                  required_values.add(str(node.op.child))
> >  
> >          for atom in self.atoms:
> >              if atom.lower() not in required_values:
> >                  continue
> > -            buf.append("\tbool %s = test_bit(LTL_%s, mon->atoms);" %
> > (atom.lower(), atom))
> > +            buf.append(f"\tbool {atom.lower()} = test_bit(LTL_{atom}, mon-
> > >atoms);")
> >  
> >          buf.reverse()
> >  
> > @@ -153,7 +153,7 @@ class ltl2k(generator.Monitor):
> >          ])
> >  
> >          for node in self.ba:
> > -            buf.append("\tcase S%i:" % node.id)
> > +            buf.append(f"\tcase S{node.id}:")
> >  
> >              for o in sorted(node.outgoing):
> >                  line   = "\t\tif "
> > @@ -163,7 +163,7 @@ class ltl2k(generator.Monitor):
> >                  lines = break_long_line(line, indent)
> >                  buf.extend(lines)
> >  
> > -                buf.append("\t\t\t__set_bit(S%i, next);" % o.id)
> > +                buf.append(f"\t\t\t__set_bit(S{o.id}, next);")
> >              buf.append("\t\tbreak;")
> >          buf.extend([
> >              "\t}",
> > @@ -197,7 +197,7 @@ class ltl2k(generator.Monitor):
> >              lines = break_long_line(line, indent)
> >              buf.extend(lines)
> >  
> > -            buf.append("\t\t__set_bit(S%i, mon->states);" % node.id)
> > +            buf.append(f"\t\t__set_bit(S{node.id}, mon->states);")
> >          buf.append("}")
> >          return buf
> >  
> > @@ -205,23 +205,21 @@ class ltl2k(generator.Monitor):
> >          buff = []
> >          buff.append("static void handle_example_event(void *data, /* XXX:
> > fill header */)")
> >          buff.append("{")
> > -        buff.append("\tltl_atom_update(task, LTL_%s, true/false);" %
> > self.atoms[0])
> > +        buff.append(f"\tltl_atom_update(task, LTL_{self.atoms[0]},
> > true/false);")
> >          buff.append("}")
> >          buff.append("")
> >          return '\n'.join(buff)
> >  
> >      def fill_tracepoint_attach_probe(self):
> > -        return "\trv_attach_trace_probe(\"%s\", /* XXX: tracepoint */,
> > handle_example_event);" \
> > -                % self.name
> > +        return f"\trv_attach_trace_probe(\"{self.name}\", /* XXX: tracepoint
> > */, handle_example_event);"
> >  
> >      def fill_tracepoint_detach_helper(self):
> > -        return "\trv_detach_trace_probe(\"%s\", /* XXX: tracepoint */,
> > handle_sample_event);" \
> > -                % self.name
> > +        return f"\trv_detach_trace_probe(\"{self.name}\", /* XXX: tracepoint
> > */, handle_sample_event);"
> >  
> >      def fill_atoms_init(self):
> >          buff = []
> >          for a in self.atoms:
> > -            buff.append("\tltl_atom_set(mon, LTL_%s, true/false);" % a)
> > +            buff.append(f"\tltl_atom_set(mon, LTL_{a}, true/false);")
> >          return '\n'.join(buff)
> >  
> >      def fill_model_h(self):