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: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-id: 20180621150254.4922-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2018-06-21 16:02:54 +01:00
parent d071f4cd55
commit ec09f87753
4 changed files with 7 additions and 4 deletions

View File

@ -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.

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@ -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"

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@ -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"

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@ -53,8 +53,6 @@ def out(*lines, **kwargs):
"bool",
"unsigned",
"signed",
"float",
"double",
"int8_t",
"uint8_t",
"int16_t",