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Message-ID: <20120822084322.17293.70186.stgit@ltc189.sdl.hitachi.co.jp>
Date: Wed, 22 Aug 2012 17:43:22 +0900
From: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: Amit Shah <amit.shah@...hat.com>,
Anthony Liguori <anthony@...emonkey.ws>,
Arnd Bergmann <arnd@...db.de>, Borislav Petkov <bp@...64.org>,
"Franch Ch. Eigler" <fche@...hat.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Herbert Xu <herbert@...dor.apana.org.au>,
Ingo Molnar <mingo@...hat.com>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Rusty Russell <rusty@...tcorp.com.au>,
linux-kernel@...r.kernel.org,
virtualization@...ts.linux-foundation.org, qemu-devel@...gnu.org,
yrl.pp-manager.tt@...achi.com,
Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
Subject: [PATCH 3/5] trace-cmd: Support trace-agent of virtio-trace
Add read path and control path to use trace-agent of virtio-trace.
When we use trace-agent, trace-cmd will be used as follows:
# AGENT_READ_DIR=/tmp/virtio-trace/tracing \
AGENT_CTL=/tmp/virtio-trace/agent-ctl-path.in \
TRACING_DIR=/tmp/virtio-trace/debugfs/tracing \
trace-cmd record -e "sched:*"
Here, AGENT_READ_DIR is the path for a reading directory of virtio-trace,
AGENT_CTL is a control path of trace-agent, and TRACING_DIR is a debugfs path
of a guest.
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
---
trace-cmd.h | 1 +
trace-recorder.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
trace-util.c | 18 +++++++++++++++++
3 files changed, 75 insertions(+), 1 deletions(-)
diff --git a/trace-cmd.h b/trace-cmd.h
index f904dc5..75506ed 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -72,6 +72,7 @@ static inline int tracecmd_host_bigendian(void)
}
char *tracecmd_find_tracing_dir(void);
+char *guest_agent_tracing_read_dir(void);
/* --- Opening and Reading the trace.dat file --- */
diff --git a/trace-recorder.c b/trace-recorder.c
index 215affc..3b750e9 100644
--- a/trace-recorder.c
+++ b/trace-recorder.c
@@ -33,6 +33,7 @@
#include <unistd.h>
#include <ctype.h>
#include <errno.h>
+#include <stdbool.h>
#include "trace-cmd.h"
@@ -43,6 +44,8 @@ struct tracecmd_recorder {
int page_size;
int cpu;
int stop;
+ int ctl_fd;
+ bool agent_existing;
};
void tracecmd_free_recorder(struct tracecmd_recorder *recorder)
@@ -59,11 +62,29 @@ void tracecmd_free_recorder(struct tracecmd_recorder *recorder)
free(recorder);
}
+static char *use_trace_agent_dir(char *ctl_path,
+ struct tracecmd_recorder *recorder)
+{
+ ctl_path = strdup(ctl_path);
+ if (!ctl_path)
+ die("malloc");
+ warning("Use environmental control path: %s\n", ctl_path);
+
+ recorder->ctl_fd = open(ctl_path, O_WRONLY);
+ if (recorder->ctl_fd < 0)
+ return NULL;
+
+ recorder->agent_existing = true;
+
+ return guest_agent_tracing_read_dir();
+}
+
struct tracecmd_recorder *tracecmd_create_recorder_fd(int fd, int cpu)
{
struct tracecmd_recorder *recorder;
char *tracing = NULL;
char *path = NULL;
+ char *ctl_path = NULL;
int ret;
recorder = malloc_or_die(sizeof(*recorder));
@@ -76,12 +97,23 @@ struct tracecmd_recorder *tracecmd_create_recorder_fd(int fd, int cpu)
recorder->trace_fd = -1;
recorder->brass[0] = -1;
recorder->brass[1] = -1;
+ recorder->ctl_fd = -1;
+ recorder->agent_existing = false;
recorder->page_size = getpagesize();
recorder->fd = fd;
- tracing = tracecmd_find_tracing_dir();
+ /*
+ * The trace-agent on a guest is controlled to run or stop by a host,
+ * so we need to assign the control path of the trace-agent to use
+ * virtio-trace.
+ */
+ ctl_path = getenv("AGENT_CTL");
+ if (ctl_path)
+ tracing = use_trace_agent_dir(ctl_path, recorder);
+ else
+ tracing = tracecmd_find_tracing_dir();
if (!tracing) {
errno = ENODEV;
goto out_free;
@@ -182,6 +214,24 @@ long tracecmd_flush_recording(struct tracecmd_recorder *recorder)
return total;
}
+static void operation_to_trace_agent(int ctl_fd, bool run_agent)
+{
+ if (run_agent == true)
+ write(ctl_fd, "1", 2);
+ else
+ write(ctl_fd, "0", 2);
+}
+
+static void run_operation_to_trace_agent(int ctl_fd)
+{
+ operation_to_trace_agent(ctl_fd, true);
+}
+
+static void stop_operation_to_trace_agent(int ctl_fd)
+{
+ operation_to_trace_agent(ctl_fd, false);
+}
+
int tracecmd_start_recording(struct tracecmd_recorder *recorder, unsigned long sleep)
{
struct timespec req;
@@ -189,6 +239,9 @@ int tracecmd_start_recording(struct tracecmd_recorder *recorder, unsigned long s
recorder->stop = 0;
+ if (recorder->agent_existing)
+ run_operation_to_trace_agent(recorder->ctl_fd);
+
do {
if (sleep) {
req.tv_sec = sleep / 1000000;
@@ -214,6 +267,8 @@ void tracecmd_stop_recording(struct tracecmd_recorder *recorder)
if (!recorder)
return;
+ if (recorder->agent_existing)
+ stop_operation_to_trace_agent(recorder->ctl_fd);
recorder->stop = 1;
}
diff --git a/trace-util.c b/trace-util.c
index d5a3eb4..ff639be 100644
--- a/trace-util.c
+++ b/trace-util.c
@@ -304,6 +304,24 @@ static int mount_debugfs(void)
return ret;
}
+char *guest_agent_tracing_read_dir(void)
+{
+ char *tracing_read_dir;
+
+ tracing_read_dir = getenv("AGENT_READ_DIR");
+ if (tracing_read_dir) {
+ tracing_read_dir = strdup(tracing_read_dir);
+ if (!tracing_read_dir)
+ die("malloc");
+ warning("Use environmental read directory of trace-agent: %s\n",
+ tracing_read_dir);
+ return tracing_read_dir;
+ }
+
+ warning("AGENT_READ_DIR was not declared");
+ return NULL;
+}
+
char *tracecmd_find_tracing_dir(void)
{
char debugfs[MAX_PATH+1];
--
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