Commit 93977402 authored by Daniel P. Berrangé's avatar Daniel P. Berrangé Committed by Stefan Hajnoczi
Browse files

trace: remove global 'uint16 dstate[]' array 



Instead of having a global dstate array, declare a single
'uint16 TRACE_${EVENT_NAME}_DSTATE' variable for each
trace event. Record a pointer to this variable in the
TraceEvent struct too.

By turning trace_event_get_state_dynamic_by_id into a
macro, this still hits the fast path, and cache affinity
is ensured by declaring all the uint16 vars adjacent to
each other.

Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarLluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-7-git-send-email-berrange@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 599ab2f2

scripts/tracetool/__init__.py

+2 −1
Original line number Diff line number Diff line
@@ -265,11 +265,12 @@ class Event(object): 


    QEMU_TRACE               = "trace_%(name)s"

    QEMU_TRACE_TCG           = QEMU_TRACE + "_tcg"

    QEMU_DSTATE              = "_TRACE_%(NAME)s_DSTATE"



    def api(self, fmt=None):

        if fmt is None:

            fmt = Event.QEMU_TRACE

        return fmt % {"name": self.name}

        return fmt % {"name": self.name, "NAME": self.name.upper()}



    def transform(self, *trans):

        """Return a new Event with transformed Arguments."""

scripts/tracetool/format/events_c.py

+7 −2
Original line number Diff line number Diff line
@@ -25,6 +25,9 @@ def generate(events, backend): 
        '#include "trace/control.h"',

        '')



    for e in events:

        out('uint16_t %s;' % e.api(e.QEMU_DSTATE))



    out('TraceEvent trace_events[TRACE_EVENT_COUNT] = {')



    for e in events:
@@ -34,11 +37,13 @@ def generate(events, backend): 
            vcpu_id = "TRACE_VCPU_EVENT_COUNT"

        out('    { .id = %(id)s, .vcpu_id = %(vcpu_id)s,'

            ' .name = \"%(name)s\",'

            ' .sstate = %(sstate)s },',

            ' .sstate = %(sstate)s,',

            ' .dstate = &%(dstate)s, }, ',

            id = "TRACE_" + e.name.upper(),

            vcpu_id = vcpu_id,

            name = e.name,

            sstate = "TRACE_%s_ENABLED" % e.name.upper())

            sstate = "TRACE_%s_ENABLED" % e.name.upper(),

            dstate = e.api(e.QEMU_DSTATE))



    out('};',

        '')

scripts/tracetool/format/events_h.py

+3 −0
Original line number Diff line number Diff line
@@ -32,6 +32,9 @@ def generate(events, backend): 
    out('    TRACE_EVENT_COUNT',

        '} TraceEventID;')



    for e in events:

        out('extern uint16_t %s;' % e.api(e.QEMU_DSTATE))



    # per-vCPU event identifiers

    out('typedef enum {')

stubs/trace-control.c

+4 −5
Original line number Diff line number Diff line
@@ -18,22 +18,21 @@ void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state) 


void trace_event_set_state_dynamic(TraceEvent *ev, bool state)

{

    TraceEventID id;

    bool state_pre;

    assert(trace_event_get_state_static(ev));

    id = trace_event_get_id(ev);



    /*

     * We ignore the "vcpu" property here, since there's no target code. Then

     * dstate can only be 1 or 0.

     */

    state_pre = trace_events_dstate[id];

    state_pre = *(ev->dstate);

    if (state_pre != state) {

        if (state) {

            trace_events_enabled_count++;

            trace_events_dstate[id] = 1;

            *(ev->dstate) = 1;

        } else {

            trace_events_enabled_count--;

            trace_events_dstate[id] = 0;

            *(ev->dstate) = 0;

        }

    }

}

trace/control-internal.h

+4 −10
Original line number Diff line number Diff line
@@ -16,7 +16,6 @@ 




extern TraceEvent trace_events[];

extern uint16_t trace_events_dstate[];

extern int trace_events_enabled_count;
@@ -54,18 +53,13 @@ static inline bool trace_event_get_state_static(TraceEvent *ev) 
    return ev->sstate;

}



static inline bool trace_event_get_state_dynamic_by_id(TraceEventID id)

{

/* it's on fast path, avoid consistency checks (asserts) */

    return unlikely(trace_events_enabled_count) && trace_events_dstate[id];

}

#define trace_event_get_state_dynamic_by_id(id) \

    (unlikely(trace_events_enabled_count) && _ ## id ## _DSTATE)



static inline bool trace_event_get_state_dynamic(TraceEvent *ev)

{

    TraceEventID id;

    assert(trace_event_get_state_static(ev));

    id = trace_event_get_id(ev);

    return trace_event_get_state_dynamic_by_id(id);

    return unlikely(trace_events_enabled_count) && *ev->dstate;

}



static inline bool trace_event_get_vcpu_state_dynamic_by_vcpu_id(CPUState *vcpu,