This patch introduces a basic example, showing how to use the
C API of KernelShark in order to filter trace data.
Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@xxxxxxxxx>
---
kernel-shark-qt/examples/CMakeLists.txt | 4 +
kernel-shark-qt/examples/datafilter.c | 114 ++++++++++++++++++++++++
2 files changed, 118 insertions(+)
create mode 100644 kernel-shark-qt/examples/datafilter.c
diff --git a/kernel-shark-qt/examples/CMakeLists.txt b/kernel-shark-qt/examples/CMakeLists.txt
index 98df9d8..009fd1e 100644
--- a/kernel-shark-qt/examples/CMakeLists.txt
+++ b/kernel-shark-qt/examples/CMakeLists.txt
@@ -3,3 +3,7 @@ message("\n examples ...")
message(STATUS "dataload")
add_executable(dload dataload.c)
target_link_libraries(dload kshark)
+
+message(STATUS "datafilter")
+add_executable(dfilter datafilter.c)
+target_link_libraries(dfilter kshark)
diff --git a/kernel-shark-qt/examples/datafilter.c b/kernel-shark-qt/examples/datafilter.c
new file mode 100644
index 0000000..e824880
--- /dev/null
+++ b/kernel-shark-qt/examples/datafilter.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2018 VMware Inc, Yordan Karadzhov <y.karadz@xxxxxxxxx>
+ */
+
+// C
+#include <stdio.h>
+#include <stdlib.h>
+
+// KernelShark
+#include "libkshark.h"
+
+const char *default_file = "trace.dat";
+
+int main(int argc, char **argv)
+{
+ // Create a new kshark session.
+ struct kshark_context *kshark_ctx = NULL;
+ kshark_instance(&kshark_ctx);
+
+ // Open a trace data file produced by trace-cmd.
+ bool status;
+ if (argc > 1)
+ status = kshark_open(kshark_ctx, argv[1]);
+ else
+ status = kshark_open(kshark_ctx, default_file);
+
+ if (!status) {
+ kshark_free(kshark_ctx);
+ return 1;
+ }
+
+ // Load the content of the file into an array of entries.
+ struct kshark_entry **data = NULL;
+ size_t n_rows;
+ n_rows = kshark_load_data_entries(kshark_ctx, &data);
+
+ // Filter the trace data coming from trace-cmd.
+ struct kshark_task_list* task = kshark_ctx->tasks;
+ while (task) {
+ const char *task_str = pevent_data_comm_from_pid(kshark_ctx->pevt,
+ task->pid);
+
+ if (strcmp(task_str, "trace-cmd") == 0)
+ kshark_filter_add_id(kshark_ctx, HIDE_TASK_FILTER,
+ task->pid);
+
+ task = task->next;
+ }
+
+ /*
+ * Set the Filter Mask. In this case we want to avoid showing the filterd
+ * entris in text format.
+ */
+ kshark_ctx->filter_mask = KS_TEXT_VIEW_FILTER_MASK;
+
+ kshark_filter_entries(kshark_ctx, data, n_rows);
+
+ // Print to the screen the first 10 visible entries.
+ char *entry_str;
+ size_t r = 0, count = 0;
+ while (count < 10) {
+ if (data[r]->visible & KS_TEXT_VIEW_FILTER_MASK) {
+ entry_str = kshark_dump_entry(data[r]);
+ puts(entry_str);
+ free(entry_str);
+ ++count;
+ }
+
+ ++r;
+ }
+
+ puts("\n\n");
+
+ struct event_format *event;
+ size_t i, n_evts = kshark_ctx->pevt->nr_events;
+ for (i = 0; i < n_evts; ++i) {
+ event = kshark_ctx->pevt->events[i];
+ if (strcmp(event->system, "sched") == 0)
+ kshark_filter_add_id(kshark_ctx, SHOW_EVENT_FILTER,
+ event->id);
+ }
+
+ kshark_filter_entries(kshark_ctx, data, n_rows);
+
+ // Print to the screen the first 10 visible entries.
+ count = 0;
+ r = 0;
+ while (count < 10) {
+ if (data[r]->visible & KS_TEXT_VIEW_FILTER_MASK) {
+ entry_str = kshark_dump_entry(data[r]);
+ puts(entry_str);
+ free(entry_str);
+ ++count;
+ }
+
+ ++r;
+ }
+
+ // Free the memory.
+ for (r = 0; r < n_rows; ++r)
+ free(data[r]);
+
+ free(data);
+
+ // Close the file.
+ kshark_close(kshark_ctx);
+
+ // Close the session.
+ kshark_free(kshark_ctx);
+
+ return 0;
+}
--
2.17.1
|