perf: 'perf kvm' tool for monitoring guest performance from host

Here is the patch of userspace perf tool.

Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 60 insertions, 3 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index a1b99eeac3c0..27f992aca8b5 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -456,6 +456,52 @@ static void atexit_header(void)
         }
 }
 
+static void event__synthesize_guest_os(struct kernel_info *kerninfo,
+                void *data __attribute__((unused)))
+{
+        int err;
+        char *guest_kallsyms;
+        char path[PATH_MAX];
+
+        if (is_host_kernel(kerninfo))
+                return;
+
+        /*
+         *As for guest kernel when processing subcommand record&report,
+         *we arrange module mmap prior to guest kernel mmap and trigger
+         *a preload dso because default guest module symbols are loaded
+         *from guest kallsyms instead of /lib/modules/XXX/XXX. This
+         *method is used to avoid symbol missing when the first addr is
+         *in module instead of in guest kernel.
+         */
+        err = event__synthesize_modules(process_synthesized_event,
+                        session,
+                        kerninfo);
+        if (err < 0)
+                pr_err("Couldn't record guest kernel [%d]'s reference"
+                        " relocation symbol.\n", kerninfo->pid);
+
+        if (is_default_guest(kerninfo))
+                guest_kallsyms = (char *) symbol_conf.default_guest_kallsyms;
+        else {
+                sprintf(path, "%s/proc/kallsyms", kerninfo->root_dir);
+                guest_kallsyms = path;
+        }
+
+        /*
+         * We use _stext for guest kernel because guest kernel's /proc/kallsyms
+         * have no _text sometimes.
+         */
+        err = event__synthesize_kernel_mmap(process_synthesized_event,
+                        session, kerninfo, "_text");
+        if (err < 0)
+                err = event__synthesize_kernel_mmap(process_synthesized_event,
+                                session, kerninfo, "_stext");
+        if (err < 0)
+                pr_err("Couldn't record guest kernel [%d]'s reference"
+                        " relocation symbol.\n", kerninfo->pid);
+}
+
 static int __cmd_record(int argc, const char **argv)
 {
         int i, counter;
@@ -467,6 +513,7 @@ static int __cmd_record(int argc, const char **argv)
         int child_ready_pipe[2], go_pipe[2];
         const bool forks = argc > 0;
         char buf;
+        struct kernel_info *kerninfo;
 
         page_size = sysconf(_SC_PAGE_SIZE);
 
@@ -635,21 +682,31 @@ static int __cmd_record(int argc, const char **argv)
                 advance_output(err);
         }
 
+        kerninfo = kerninfo__findhost(&session->kerninfo_root);
+        if (!kerninfo) {
+                pr_err("Couldn't find native kernel information.\n");
+                return -1;
+        }
+
         err = event__synthesize_kernel_mmap(process_synthesized_event,
-                                            session, "_text");
+                        session, kerninfo, "_text");
         if (err < 0)
                 err = event__synthesize_kernel_mmap(process_synthesized_event,
-                                                    session, "_stext");
+                                session, kerninfo, "_stext");
         if (err < 0) {
                 pr_err("Couldn't record kernel reference relocation symbol.\n");
                 return err;
         }
 
-        err = event__synthesize_modules(process_synthesized_event, session);
+        err = event__synthesize_modules(process_synthesized_event,
+                                session, kerninfo);
         if (err < 0) {
                 pr_err("Couldn't record kernel reference relocation symbol.\n");
                 return err;
         }
+        if (perf_guest)
+                kerninfo__process_allkernels(&session->kerninfo_root,
+                        event__synthesize_guest_os, session);
 
         if (!system_wide && profile_cpu == -1)
                 event__synthesize_thread(target_tid, process_synthesized_event,