To help for the performance optimizations and debugging, this patch tracepoints
for vhost. Two kinds of activities were traced: virtio and vhost work
queuing/wakeup.
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/vhost/net.c | 1 +
drivers/vhost/trace.h | 175 ++++++++++++++++++++++++++++++++++++++++++++++++++
drivers/vhost/vhost.c | 14 +++-
3 files changed, 189 insertions(+), 1 deletion(-)
create mode 100644 drivers/vhost/trace.h
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 85d666c..7353204 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1,3 +1,4 @@
+
/* Copyright (C) 2009 Red Hat, Inc.
* Author: Michael S. Tsirkin <mst@xxxxxxxxxx>
*
diff --git a/drivers/vhost/trace.h b/drivers/vhost/trace.h
new file mode 100644
index 0000000..e380942
--- /dev/null
+++ b/drivers/vhost/trace.h
@@ -0,0 +1,175 @@
+#if !defined(_TRACE_VHOST_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_VHOST_H
+
+#include <linux/tracepoint.h>
+#include "vhost.h"
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM vhost
+
+/*
+ * Tracepoint for updating used flag.
+ */
+TRACE_EVENT(vhost_virtio_update_used_flags,
+ TP_PROTO(struct vhost_virtqueue *vq),
+ TP_ARGS(vq),
+
+ TP_STRUCT__entry(
+ __field(struct vhost_virtqueue *, vq)
+ __field(u16, queue_index)
+ __field(u16, used_flags)
+ ),
+
+ TP_fast_assign(
+ __entry->vq = vq;
+ __entry->queue_index = vq->queue_index;
+ __entry->used_flags = vq->used_flags;
+ ),
+
+ TP_printk("vhost update used flag %x to vq %d notify %s",
+ __entry->used_flags, __entry->queue_index,
+ (__entry->used_flags & VRING_USED_F_NO_NOTIFY) ?
+ "disabled" : "enabled")
+);
+
+/*
+ * Tracepoint for updating avail event.
+ */
+TRACE_EVENT(vhost_virtio_update_avail_event,
+ TP_PROTO(struct vhost_virtqueue *vq),
+ TP_ARGS(vq),
+
+ TP_STRUCT__entry(
+ __field(struct vhost_virtqueue *, vq)
+ __field(u16, queue_index)
+ __field(u16, avail_idx)
+ ),
+
+ TP_fast_assign(
+ __entry->vq = vq;
+ __entry->queue_index = vq->queue_index;
+ __entry->avail_idx = vq->avail_idx;
+ ),
+
+ TP_printk("vhost update avail event %u(%u) for vq %d",
+ __entry->avail_idx, __entry->avail_idx %
+ __entry->vq->num, __entry->queue_index)
+);
+
+/*
+ * Tracepoint for updating used index.
+ */
+TRACE_EVENT(vhost_virtio_update_used_idx,
+ TP_PROTO(struct vhost_virtqueue *vq),
+ TP_ARGS(vq),
+
+ TP_STRUCT__entry(
+ __field(struct vhost_virtqueue *, vq)
+ __field(u16, queue_index)
+ __field(u16, used_idx)
+ ),
+
+ TP_fast_assign(
+ __entry->vq = vq;
+ __entry->queue_index = vq->queue_index;
+ __entry->used_idx = vq->last_used_idx;
+ ),
+
+ TP_printk("vhost update used index %u(%u) for vq %d",
+ __entry->used_idx, __entry->used_idx %
+ __entry->vq->num, __entry->queue_index)
+);
+
+/*
+ * Tracepoint for processing descriptor.
+ */
+TRACE_EVENT(vhost_virtio_get_vq_desc,
+ TP_PROTO(struct vhost_virtqueue *vq, unsigned int index,
+ unsigned out, unsigned int in),
+ TP_ARGS(vq, index, out, in),
+
+ TP_STRUCT__entry(
+ __field(struct vhost_virtqueue *, vq)
+ __field(u16, queue_index)
+ __field(unsigned int, head)
+ __field(unsigned int, out)
+ __field(unsigned int, in)
+ __field(u16, last_avail_idx)
+ ),
+
+ TP_fast_assign(
+ __entry->vq = vq;
+ __entry->queue_index = vq->queue_index;
+ __entry->head = index;
+ __entry->out = out;
+ __entry->in = in;
+ __entry->last_avail_idx = vq->last_avail_idx;
+ ),
+
+ TP_printk("vhost get vq %d desc last avail index %u(%u), "
+ "head %u out %u in %u",
+ __entry->queue_index,
+ __entry->last_avail_idx,
+ __entry->last_avail_idx % __entry->vq->num,
+ __entry->head, __entry->out, __entry->in)
+);
+
+/*
+ * Tracepoint for signal guest.
+ */
+TRACE_EVENT(vhost_virtio_signal,
+ TP_PROTO(struct vhost_virtqueue *vq),
+ TP_ARGS(vq),
+
+ TP_STRUCT__entry(
+ __field(u16, queue_index)
+ ),
+
+ TP_fast_assign(
+ __entry->queue_index = vq->queue_index;
+ ),
+
+ TP_printk("vhost signal vq %d", __entry->queue_index)
+);
+
+DECLARE_EVENT_CLASS(vhost_work_template,
+ TP_PROTO(struct vhost_work *work),
+ TP_ARGS(work),
+
+ TP_STRUCT__entry(
+ __field(void *, function)
+ ),
+
+ TP_fast_assign(
+ __entry->function = work->fn;
+ ),
+
+ TP_printk("%pf", __entry->function)
+);
+
+DEFINE_EVENT(vhost_work_template, vhost_work_queue_wakeup,
+ TP_PROTO(struct vhost_work *work),
+ TP_ARGS(work));
+
+DEFINE_EVENT(vhost_work_template, vhost_work_queue_coalesce,
+ TP_PROTO(struct vhost_work *work),
+ TP_ARGS(work));
+
+DEFINE_EVENT(vhost_work_template, vhost_poll_start,
+ TP_PROTO(struct vhost_work *work),
+ TP_ARGS(work));
+
+DEFINE_EVENT(vhost_work_template, vhost_poll_stop,
+ TP_PROTO(struct vhost_work *work),
+ TP_ARGS(work));
+
+#endif /* _TRACE_VHOST_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH ../../drivers/vhost
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
+
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 78987e4..7cf3d6e 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -28,6 +28,8 @@
#include <linux/module.h>
#include "vhost.h"
+#define CREATE_TRACE_POINTS
+#include "trace.h"
enum {
VHOST_MEMORY_MAX_NREGIONS = 64,
@@ -45,6 +47,7 @@ static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
poll = container_of(pt, struct vhost_poll, table);
poll->wqh = wqh;
add_wait_queue(wqh, &poll->wait);
+ trace_vhost_poll_start(&poll->work);
}
static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync,
@@ -114,6 +117,7 @@ void vhost_poll_stop(struct vhost_poll *poll)
remove_wait_queue(poll->wqh, &poll->wait);
poll->wqh = NULL;
}
+ trace_vhost_poll_stop(&poll->work);
}
EXPORT_SYMBOL_GPL(vhost_poll_stop);
@@ -163,8 +167,10 @@ void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
work->queue_seq++;
spin_unlock_irqrestore(&dev->work_lock, flags);
wake_up_process(dev->worker);
+ trace_vhost_work_queue_wakeup(work);
} else {
spin_unlock_irqrestore(&dev->work_lock, flags);
+ trace_vhost_work_queue_coalesce(work);
}
}
EXPORT_SYMBOL_GPL(vhost_work_queue);
@@ -1008,6 +1014,7 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
if (vq->log_ctx)
eventfd_signal(vq->log_ctx, 1);
}
+ trace_vhost_virtio_update_used_flags(vq);
return 0;
}
@@ -1027,6 +1034,7 @@ static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
if (vq->log_ctx)
eventfd_signal(vq->log_ctx, 1);
}
+ trace_vhost_virtio_update_avail_event(vq);
return 0;
}
@@ -1311,6 +1319,7 @@ int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
}
} while ((i = next_desc(&desc)) != -1);
+ trace_vhost_virtio_get_vq_desc(vq, head, *out_num, *in_num);
/* On success, increment avail index. */
vq->last_avail_idx++;
@@ -1405,6 +1414,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
vq_err(vq, "Failed to increment used idx");
return -EFAULT;
}
+ trace_vhost_virtio_update_used_idx(vq);
if (unlikely(vq->log_used)) {
/* Log used index update. */
log_write(vq->log_base,
@@ -1457,8 +1467,10 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
/* Signal the Guest tell them we used something up. */
- if (vq->call_ctx && vhost_notify(dev, vq))
+ if (vq->call_ctx && vhost_notify(dev, vq)) {
eventfd_signal(vq->call_ctx, 1);
+ trace_vhost_virtio_signal(vq);
+ }
}
EXPORT_SYMBOL_GPL(vhost_signal);
--
1.8.3.2
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