Commit ec09f877 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi
Browse files

trace: forbid floating point types 



Only one existing trace event uses a floating point type.  Unfortunately
float and double cannot be supported since SystemTap does not have
floating point types.

Remove float and double from the whitelist and document this limitation.
Update the migrate_transferred trace event to use uint64_t instead of
double.

Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Daniel P. Berrangé <berrange@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: default avatarJuan Quintela <quintela@redhat.com>
Message-id: 20180621150254.4922-1-stefanha@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent d071f4cd

docs/devel/tracing.txt

+5 −0
Original line number Diff line number Diff line
@@ -104,6 +104,11 @@ Trace events should use types as follows: 
 * For everything else, use primitive scalar types (char, int, long) with the

   appropriate signedness.



 * Avoid floating point types (float and double) because SystemTap does not

   support them.  In most cases it is possible to round to an integer type

   instead.  This may require scaling the value first by multiplying it by 1000

   or the like when digits after the decimal point need to be preserved.



Format strings should reflect the types defined in the trace event.  Take

special care to use PRId64 and PRIu64 for int64_t and uint64_t types,

respectively.  This ensures portability between 32- and 64-bit platforms.

migration/trace-events

+1 −1
Original line number Diff line number Diff line
@@ -133,7 +133,7 @@ migrate_global_state_post_load(const char *state) "loaded state: %s" 
migrate_global_state_pre_save(const char *state) "saved state: %s"

migration_thread_low_pending(uint64_t pending) "%" PRIu64

migrate_state_too_big(void) ""

migrate_transferred(uint64_t tranferred, uint64_t time_spent, double bandwidth, uint64_t size) "transferred %" PRIu64 " time_spent %" PRIu64 " bandwidth %g max_size %" PRId64

migrate_transferred(uint64_t tranferred, uint64_t time_spent, uint64_t bandwidth, uint64_t size) "transferred %" PRIu64 " time_spent %" PRIu64 " bandwidth %" PRIu64 " max_size %" PRId64

process_incoming_migration_co_end(int ret, int ps) "ret=%d postcopy-state=%d"

process_incoming_migration_co_postcopy_end_main(void) ""

migration_set_incoming_channel(void *ioc, const char *ioctype) "ioc=%p ioctype=%s"

qapi/trace-events

+1 −1
Original line number Diff line number Diff line
@@ -29,6 +29,6 @@ visit_type_int64(void *v, const char *name, int64_t *obj) "v=%p name=%s obj=%p" 
visit_type_size(void *v, const char *name, uint64_t *obj) "v=%p name=%s obj=%p"

visit_type_bool(void *v, const char *name, bool *obj) "v=%p name=%s obj=%p"

visit_type_str(void *v, const char *name, char **obj) "v=%p name=%s obj=%p"

visit_type_number(void *v, const char *name, double *obj) "v=%p name=%s obj=%p"

visit_type_number(void *v, const char *name, void *obj) "v=%p name=%s obj=%p"

visit_type_any(void *v, const char *name, void *obj) "v=%p name=%s obj=%p"

visit_type_null(void *v, const char *name, void *obj) "v=%p name=%s obj=%p"

scripts/tracetool/__init__.py

+0 −2
Original line number Diff line number Diff line
@@ -53,8 +53,6 @@ ALLOWED_TYPES = [ 
    "bool",

    "unsigned",

    "signed",

    "float",

    "double",

    "int8_t",

    "uint8_t",

    "int16_t",