[RFC][PATCH 002/002] Add timestamp field to process events

Matt Helsley
2005-12-06T05:16:53Z

This patch adds a timestamp field to the events sent via the process
event connector. The timestamp allows listeners to accurately account the
duration(s) between a process' events and offers strong means with which to
determine the order of events with respect to a given task while also avoiding
the addition of per-task data.

This alters the size and layout of the event structure and hence would
break compatibility if process events connector as it stands in 2.6.15-rc2 were
released as a mainline kernel.

Signed-off-by: Matt Helsley <matthltc@us.ibm.com>

--

Index: linux-2.6.15-rc5/drivers/connector/cn_proc.c
===================================================================
--- linux-2.6.15-rc5.orig/drivers/connector/cn_proc.c
+++ linux-2.6.15-rc5/drivers/connector/cn_proc.c
@@ -54,10 +54,11 @@ void proc_fork_connector(struct task_str
return;

msg = (struct cn_msg*)buffer;
ev = (struct proc_event*)msg->data;
get_seq(&msg->seq, &ev->cpu);
+ getnstimestamp(&ev->timestamp);
ev->what = PROC_EVENT_FORK;
ev->event_data.fork.parent_pid = task->real_parent->pid;
ev->event_data.fork.parent_tgid = task->real_parent->tgid;
ev->event_data.fork.child_pid = task->pid;
ev->event_data.fork.child_tgid = task->tgid;
@@ -79,10 +80,11 @@ void proc_exec_connector(struct task_str
return;

msg = (struct cn_msg*)buffer;
ev = (struct proc_event*)msg->data;
get_seq(&msg->seq, &ev->cpu);
+ getnstimestamp(&ev->timestamp);
ev->what = PROC_EVENT_EXEC;
ev->event_data.exec.process_pid = task->pid;
ev->event_data.exec.process_tgid = task->tgid;

memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
@@ -112,10 +114,11 @@ void proc_id_connector(struct task_struc
ev->event_data.id.r.rgid = task->gid;
ev->event_data.id.e.egid = task->egid;
} else
return;
get_seq(&msg->seq, &ev->cpu);
+ getnstimestamp(&ev->timestamp);

memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = 0; /* not used */
msg->len = sizeof(*ev);
cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
@@ -131,10 +134,11 @@ void proc_exit_connector(struct task_str
return;

msg = (struct cn_msg*)buffer;
ev = (struct proc_event*)msg->data;
get_seq(&msg->seq, &ev->cpu);
+ getnstimestamp(&ev->timestamp);
ev->what = PROC_EVENT_EXIT;
ev->event_data.exit.process_pid = task->pid;
ev->event_data.exit.process_tgid = task->tgid;
ev->event_data.exit.exit_code = task->exit_code;
ev->event_data.exit.exit_signal = task->exit_signal;
@@ -163,10 +167,11 @@ static void cn_proc_ack(int err, int rcv
return;

msg = (struct cn_msg*)buffer;
ev = (struct proc_event*)msg->data;
msg->seq = rcvd_seq;
+ getnstimestamp(&ev->timestamp);
ev->cpu = -1;
ev->what = PROC_EVENT_NONE;
ev->event_data.ack.err = err;
memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
msg->ack = rcvd_ack + 1;
Index: linux-2.6.15-rc5/include/linux/cn_proc.h
===================================================================
--- linux-2.6.15-rc5.orig/include/linux/cn_proc.h
+++ linux-2.6.15-rc5/include/linux/cn_proc.h
@@ -24,10 +24,11 @@

#ifndef CN_PROC_H
#define CN_PROC_H

#include <linux/types.h>
+#include <linux/time.h>
#include <linux/connector.h>

/*
* Userspace sends this enum to register with the kernel that it is listening
* for events on the connector.
@@ -63,10 +64,11 @@ struct proc_event {
/* "next" should be 0x00000400 */
/* "last" is the last process event: exit */
PROC_EVENT_EXIT = 0x80000000
} what;
__u32 cpu;
+ struct timespec timestamp;
union { /* must be last field of proc_event struct */
struct {
__u32 err;
} ack;