Hi Leonard,
On 19.11.19 г. 0:34 ч., Leonard Crestez wrote:
The interconnect graphs can be difficult to understand and the current
"interconnect_summary" file doesn't even display links in any way.
Add a new "interconnect_graph" file to debugfs in the graphviz "dot"
format which describes interconnect providers, nodes and links.
The file is human-readable and can be visualized by piping through
graphviz. Example:
ssh $TARGET cat /sys/kernel/debug/interconnect/interconnect_graph \
| dot -Tsvg > interconnect_graph.svg
Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---
Documentation/driver-api/interconnect.rst | 23 ++++++++
drivers/interconnect/core.c | 66 +++++++++++++++++++++++
2 files changed, 89 insertions(+)
Example output as a github gist:
https://gist.github.com/cdleonard/2f74a7efe74587e3d4b57cf7983b46a8
The qcs404 driver was hacked to probe on imx, the links to "0" seem to
from incorrect trailing 0s on DEFINE_QNODE. Possibly fallout from
switching to ARRAY_SIZE(__VA_ARGS__)?
This makes it easier to understand the interconnect graph than just
staring at registration code.
Changes since RFC v1:
* Document under driver-api/interconnect.rst
* Collect reviews
Link to v1: https://patchwork.kernel.org/patch/11242921/
diff --git a/Documentation/driver-api/interconnect.rst b/Documentation/driver-api/interconnect.rst
index cdeb5825f314..77a85aad8d2f 100644
--- a/Documentation/driver-api/interconnect.rst
+++ b/Documentation/driver-api/interconnect.rst
@@ -89,5 +89,28 @@ Interconnect consumers
Interconnect consumers are the clients which use the interconnect APIs to
get paths between endpoints and set their bandwidth/latency/QoS requirements
for these interconnect paths. These interfaces are not currently
documented.
+
+Interconnect debugfs interfaces
+-------------------------------
+
+Like several other subsystems interconnect will create some files for debugging
+and introspection. Files in debugfs are not considered ABI so application
+software shouldn't rely on format details
+change between kernel versions.
+
+``/sys/kernel/debug/interconnect/interconnect_summary``:
+
+Show all interconnect nodes in the system with their aggregated bandwith
s/bandwith/bandwidth/
+request. Indented under each node show bandwith requests from each device.
s/bandwith/bandwidth/
+
+``/sys/kernel/debug/interconnect/interconnect_graph``:
+
+Show the interconnect graph in the graphviz dot format. It shows all
+interconnect nodes and links in the system and groups together nodes from the
+same provider as subgraphs. The format is human-readable and can also be piped
+through dot to generate diagrams in many graphical formats::
+
+ $ cat /sys/kernel/debug/interconnect/interconnect_graph | \
+ dot -Tsvg > interconnect_graph.svg
diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index c498796adc07..07e91288c7f4 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -92,10 +92,74 @@ static int icc_summary_show(struct seq_file *s, void *data)
return 0;
}
DEFINE_SHOW_ATTRIBUTE(icc_summary);
+static void icc_graph_show_link(struct seq_file *s, int level,
+ struct icc_node *n, struct icc_node *m)
+{
+ seq_printf(s, "%s\"%d:%s\" -> \"%d:%s\"\n",
+ level == 2 ? "\t\t" : "\t",
+ n->id, n->name, m->id, m->name);
Nit: Should be aligned to the open parenthesis.
+}
+
+static void icc_graph_show_node(struct seq_file *s, struct icc_node *n)
+{
+ seq_printf(s, "\t\t\"%d:%s\" [label=\"%d:%s",
+ n->id, n->name, n->id, n->name);
+ seq_printf(s, "\n\t\t\t|avg_bw=%ukBps", n->avg_bw);
+ seq_printf(s, "\n\t\t\t|peak_bw=%ukBps", n->peak_bw);
+ seq_puts(s, "\"]\n");
+}
+
+static int icc_graph_show(struct seq_file *s, void *data)
+{
+ struct icc_provider *provider;
+ struct icc_node *n;
+ int cluster_index = 0;
+ int i;
+
+ seq_puts(s, "digraph {\n\trankdir = LR\n\tnode [shape = record]\n");
+ mutex_lock(&icc_lock);
+
+ /* draw providers as cluster subgraphs */
+ cluster_index = 0;
+ list_for_each_entry(provider, &icc_providers, provider_list) {
+ seq_printf(s, "\tsubgraph cluster_%d {\n", ++cluster_index);
+ if (provider->dev)
+ seq_printf(s, "\t\tlabel = \"%s\"\n",
+ dev_name(provider->dev));
+
+ /* draw nodes */
+ list_for_each_entry(n, &provider->nodes, node_list)
+ icc_graph_show_node(s, n);
+
+ /* draw internal links */
+ list_for_each_entry(n, &provider->nodes, node_list)
+ for (i = 0; i < n->num_links; ++i)
+ if (n->provider == n->links[i]->provider)
+ icc_graph_show_link(s, 2, n,
+ n->links[i]);
+
+ seq_puts(s, "\t}\n");
+ }
+
+ /* draw external links */
+ list_for_each_entry(provider, &icc_providers, provider_list)
+ list_for_each_entry(n, &provider->nodes, node_list)
+ for (i = 0; i < n->num_links; ++i)
+ if (n->provider != n->links[i]->provider)
+ icc_graph_show_link(s, 1, n,
+ n->links[i]);
+
+ mutex_unlock(&icc_lock);
+ seq_puts(s, "}");
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(icc_graph);
+
static struct icc_node *node_find(const int id)
{
return idr_find(&icc_idr, id);
}
@@ -800,10 +864,12 @@ EXPORT_SYMBOL_GPL(icc_provider_del);
static int __init icc_init(void)
{
icc_debugfs_dir = debugfs_create_dir("interconnect", NULL);
debugfs_create_file("interconnect_summary", 0444,
icc_debugfs_dir, NULL, &icc_summary_fops);
+ debugfs_create_file("interconnect_graph", 0444,
+ icc_debugfs_dir, NULL, &icc_graph_fops);
return 0;
}
static void __exit icc_exit(void)
{
This is good stuff! Thank you! I will fix up the typos while applying,
no need to resend it.
BR,
Georgi
