aboutsummaryrefslogtreecommitdiffstats
path: root/include/trace
diff options
context:
space:
mode:
authorSteven Rostedt <srostedt@redhat.com>2009-03-02 10:53:15 -0500
committerSteven Rostedt <srostedt@redhat.com>2009-03-02 10:53:15 -0500
commitd20e3b03842bfeb9d21817ff19054c277cc3eac0 (patch)
tree5de7ef8a95f9391a264df358336842c9301f3868 /include/trace
parentf2034f1e1adaac6713a6d48b5a2d4f3aa3e63ccb (diff)
downloadmrst-s0i3-test-d20e3b03842bfeb9d21817ff19054c277cc3eac0.tar.gz
mrst-s0i3-test-d20e3b03842bfeb9d21817ff19054c277cc3eac0.tar.xz
mrst-s0i3-test-d20e3b03842bfeb9d21817ff19054c277cc3eac0.zip
tracing: add TRACE_FIELD_SPECIAL to record complex entries
Tom Zanussi pointed out that the simple TRACE_FIELD was not enough to record trace data that required memcpy. This patch addresses this issue by adding a TRACE_FIELD_SPECIAL. The format is similar to TRACE_FIELD but looks like so: TRACE_FIELD_SPECIAL(type_item, item, cmd) What TRACE_FIELD gave was: TRACE_FIELD(type, item, assign) The TRACE_FIELD would be used in declaring a structure: struct { type item; }; And later assign it via: entry->item = assign; What TRACE_FIELD_SPECIAL gives us is: In the declaration of the structure: struct { type_item; }; And the assignment: cmd; This change log will explain the one example used in the patch: TRACE_EVENT_FORMAT(sched_switch, TPPROTO(struct rq *rq, struct task_struct *prev, struct task_struct *next), TPARGS(rq, prev, next), TPFMT("task %s:%d ==> %s:%d", prev->comm, prev->pid, next->comm, next->pid), TRACE_STRUCT( TRACE_FIELD(pid_t, prev_pid, prev->pid) TRACE_FIELD(int, prev_prio, prev->prio) TRACE_FIELD_SPECIAL(char next_comm[TASK_COMM_LEN], next_comm, TPCMD(memcpy(TRACE_ENTRY->next_comm, next->comm, TASK_COMM_LEN))) TRACE_FIELD(pid_t, next_pid, next->pid) TRACE_FIELD(int, next_prio, next->prio) ), TPRAWFMT("prev %d:%d ==> next %s:%d:%d") ); The struct will be create as: struct { pid_t prev_pid; int prev_prio; char next_comm[TASK_COMM_LEN]; pid_t next_pid; int next_prio; }; Note the TRACE_ENTRY in the cmd part of TRACE_SPECIAL. TRACE_ENTRY will be set by the tracer to point to the structure inside the trace buffer. entry->prev_pid = prev->pid; entry->prev_prio = prev->prio; memcpy(entry->next_comm, next->comm, TASK_COMM_LEN); entry->next_pid = next->pid; entry->next_prio = next->prio Reported-by: Tom Zanussi <tzanussi@gmail.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Diffstat (limited to 'include/trace')
-rw-r--r--include/trace/sched_event_types.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/include/trace/sched_event_types.h b/include/trace/sched_event_types.h
index ba059c10b58..a6de5c1601a 100644
--- a/include/trace/sched_event_types.h
+++ b/include/trace/sched_event_types.h
@@ -71,10 +71,15 @@ TRACE_EVENT_FORMAT(sched_switch,
TRACE_STRUCT(
TRACE_FIELD(pid_t, prev_pid, prev->pid)
TRACE_FIELD(int, prev_prio, prev->prio)
+ TRACE_FIELD_SPECIAL(char next_comm[TASK_COMM_LEN],
+ next_comm,
+ TPCMD(memcpy(TRACE_ENTRY->next_comm,
+ next->comm,
+ TASK_COMM_LEN)))
TRACE_FIELD(pid_t, next_pid, next->pid)
TRACE_FIELD(int, next_prio, next->prio)
),
- TPRAWFMT("prev %d:%d ==> next %d:%d")
+ TPRAWFMT("prev %d:%d ==> next %s:%d:%d")
);
TRACE_EVENT_FORMAT(sched_migrate_task,