The "write_bytes" curve over time is very handy for viewing the
smoothness and fairness of page dirties for each task.
XXX: It looks not a good fit for writeback traces, shall we create a
include/trace/events/vfs.h for this?
XXX: the other fields of struct task_io_accounting are not dumped.
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
include/trace/events/writeback.h | 32 +++++++++++++++++++++++++++++
mm/page-writeback.c | 1
2 files changed, 33 insertions(+)
--- linux-next.orig/include/trace/events/writeback.h 2011-08-22 11:58:21.000000000 +0800
+++ linux-next/include/trace/events/writeback.h 2011-08-22 12:22:38.000000000 +0800
@@ -180,6 +180,38 @@ TRACE_EVENT(writeback_queue_io,
__entry->moved)
);
+TRACE_EVENT(task_io,
+ TP_PROTO(struct task_struct *task),
+ TP_ARGS(task),
+
+ TP_STRUCT__entry(
+ __field(unsigned long long, read_bytes)
+ __field(unsigned long long, write_bytes)
+ __field(unsigned long long, cancelled_write_bytes)
+ ),
+
+ TP_fast_assign(
+ struct task_io_accounting *ioac = &task->ioac;
+
+#ifdef CONFIG_TASK_IO_ACCOUNTING
+ __entry->read_bytes = ioac->read_bytes;
+ __entry->write_bytes = ioac->write_bytes;
+ __entry->cancelled_write_bytes = ioac->cancelled_write_bytes;
+#else
+ __entry->read_bytes = 0;
+ __entry->write_bytes = 0;
+ __entry->cancelled_write_bytes = 0;
+#endif
+ ),
+
+ TP_printk("read=%llu write=%llu cancelled_write=%llu",
+ __entry->read_bytes,
+ __entry->write_bytes,
+ __entry->cancelled_write_bytes
+ )
+);
+
+
TRACE_EVENT(global_dirty_state,
TP_PROTO(unsigned long background_thresh,
--- linux-next.orig/mm/page-writeback.c 2011-08-22 12:10:33.000000000 +0800
+++ linux-next/mm/page-writeback.c 2011-08-22 12:20:33.000000000 +0800
@@ -407,6 +407,7 @@ void global_dirty_limits(unsigned long *
*pbackground = background;
*pdirty = dirty;
trace_global_dirty_state(background, dirty);
+ trace_task_io(current);
}
/**
--
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