Commit 864a2178 authored by Lluís Vilanova's avatar Lluís Vilanova Committed by Stefan Hajnoczi
Browse files

trace: [tcg] Do not generate TCG code to trace dynamically-disabled events 



If an event is dynamically disabled, the TCG code that calls the
execution-time tracer is not generated.

Removes the overheads of execution-time tracers for dynamically disabled
events. As a bonus, also avoids checking the event state when the
execution-time tracer is called from TCG-generated code (since otherwise
TCG would simply not call it).

Signed-off-by: default avatarLluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: default avatarEmilio G. Cota <cota@braap.org>
Message-id: 149915799921.6295.13067154430923434035.stgit@frigg.lan
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 61a67f71

scripts/tracetool/__init__.py

+2 −1
Original line number Diff line number Diff line
@@ -6,7 +6,7 @@ Machinery for generating tracing-related intermediate files. 
"""



__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"

__copyright__  = "Copyright 2012-2016, Lluís Vilanova <vilanova@ac.upc.edu>"

__copyright__  = "Copyright 2012-2017, Lluís Vilanova <vilanova@ac.upc.edu>"

__license__    = "GPL version 2 or (at your option) any later version"



__maintainer__ = "Stefan Hajnoczi"
@@ -268,6 +268,7 @@ class Event(object): 
        return self._FMT.findall(self.fmt)



    QEMU_TRACE               = "trace_%(name)s"

    QEMU_TRACE_NOCHECK       = "_nocheck__" + QEMU_TRACE

    QEMU_TRACE_TCG           = QEMU_TRACE + "_tcg"

    QEMU_DSTATE              = "_TRACE_%(NAME)s_DSTATE"

    QEMU_EVENT               = "_TRACE_%(NAME)s_EVENT"

scripts/tracetool/format/h.py

+19 −7
Original line number Diff line number Diff line
@@ -6,7 +6,7 @@ trace/generated-tracers.h 
"""



__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"

__copyright__  = "Copyright 2012-2016, Lluís Vilanova <vilanova@ac.upc.edu>"

__copyright__  = "Copyright 2012-2017, Lluís Vilanova <vilanova@ac.upc.edu>"

__license__    = "GPL version 2 or (at your option) any later version"



__maintainer__ = "Stefan Hajnoczi"
@@ -49,6 +49,19 @@ def generate(events, backend, group): 
    backend.generate_begin(events, group)



    for e in events:

        # tracer without checks

        out('',

            'static inline void %(api)s(%(args)s)',

            '{',

            api=e.api(e.QEMU_TRACE_NOCHECK),

            args=e.args)



        if "disable" not in e.properties:

            backend.generate(e, group)



        out('}')



        # tracer wrapper with checks (per-vCPU tracing)

        if "vcpu" in e.properties:

            trace_cpu = next(iter(e.args))[1]

            cond = "trace_event_get_vcpu_state(%(cpu)s,"\
@@ -63,16 +76,15 @@ def generate(events, backend, group): 
            'static inline void %(api)s(%(args)s)',

            '{',

            '    if (%(cond)s) {',

            '        %(api_nocheck)s(%(names)s);',

            '    }',

            '}',

            api=e.api(),

            api_nocheck=e.api(e.QEMU_TRACE_NOCHECK),

            args=e.args,

            names=", ".join(e.args.names()),

            cond=cond)



        if "disable" not in e.properties:

            backend.generate(e, group)



        out('    }',

            '}')



    backend.generate_end(events, group)



    out('#endif /* TRACE_%s_GENERATED_TRACERS_H */' % group.upper())

scripts/tracetool/format/tcg_h.py

+17 −4
Original line number Diff line number Diff line
@@ -6,7 +6,7 @@ Generate .h file for TCG code generation. 
"""



__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"

__copyright__  = "Copyright 2012-2016, Lluís Vilanova <vilanova@ac.upc.edu>"

__copyright__  = "Copyright 2012-2017, Lluís Vilanova <vilanova@ac.upc.edu>"

__license__    = "GPL version 2 or (at your option) any later version"



__maintainer__ = "Stefan Hajnoczi"
@@ -46,7 +46,7 @@ def generate(events, backend, group): 


    for e in events:

        # just keep one of them

        if "tcg-trans" not in e.properties:

        if "tcg-exec" not in e.properties:

            continue



        out('static inline void %(name_tcg)s(%(args)s)',
@@ -58,12 +58,25 @@ def generate(events, backend, group): 
            args_trans = e.original.event_trans.args

            args_exec = tracetool.vcpu.transform_args(

                "tcg_helper_c", e.original.event_exec, "wrapper")

            if "vcpu" in e.properties:

                trace_cpu = e.args.names()[0]

                cond = "trace_event_get_vcpu_state(%(cpu)s,"\

                       " TRACE_%(id)s)"\

                       % dict(

                           cpu=trace_cpu,

                           id=e.original.event_exec.name.upper())

            else:

                cond = "true"



            out('    %(name_trans)s(%(argnames_trans)s);',

                '    if (%(cond)s) {',

                '        gen_helper_%(name_exec)s(%(argnames_exec)s);',

                '    }',

                name_trans=e.original.event_trans.api(e.QEMU_TRACE),

                name_exec=e.original.event_exec.api(e.QEMU_TRACE),

                argnames_trans=", ".join(args_trans.names()),

                argnames_exec=", ".join(args_exec.names()))

                argnames_exec=", ".join(args_exec.names()),

                cond=cond)



        out('}')

scripts/tracetool/format/tcg_helper_c.py

+3 −2
Original line number Diff line number Diff line
@@ -6,7 +6,7 @@ Generate trace/generated-helpers.c. 
"""



__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"

__copyright__  = "Copyright 2012-2016, Lluís Vilanova <vilanova@ac.upc.edu>"

__copyright__  = "Copyright 2012-2017, Lluís Vilanova <vilanova@ac.upc.edu>"

__license__    = "GPL version 2 or (at your option) any later version"



__maintainer__ = "Stefan Hajnoczi"
@@ -71,10 +71,11 @@ def generate(events, backend, group): 


        out('void %(name_tcg)s(%(args_api)s)',

            '{',

            # NOTE: the check was already performed at TCG-generation time

            '    %(name)s(%(args_call)s);',

            '}',

            name_tcg="helper_%s_proxy" % e.api(),

            name=e.api(),

            name=e.api(e.QEMU_TRACE_NOCHECK),

            args_api=e_args_api,

            args_call=", ".join(e_args_call.casted()),

            )