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Message-ID: <20130819094647.26597.8902.stgit@yunodevel>
Date: Mon, 19 Aug 2013 18:46:47 +0900
From: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@...achi.com>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
linux-kernel@...r.kernel.org, yrl.pp-manager.tt@...achi.com
Subject: [RFC PATCH 11/11] trace-cmd: Add --virt option for record mode
Add --virt option for record mode for a virtualization environment.
If we use this option on a guest, we can send trace data in low overhead.
This is because guests can send trace data to a host without copying the data
by using splice(2).
The format is:
trace-cmd record --virt -e sched*
<Restriction>
This feature can use from kernel-3.6 which supports splice_read for ftrace
and splice_write for virtio-serial.
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
---
Documentation/trace-cmd-record.1.txt | 11 +++++-
trace-cmd.h | 3 +-
trace-msg.c | 35 ++++++++++++++++--
trace-msg.h | 4 ++
trace-record.c | 66 ++++++++++++++++++++++++++++++++--
5 files changed, 110 insertions(+), 9 deletions(-)
diff --git a/Documentation/trace-cmd-record.1.txt b/Documentation/trace-cmd-record.1.txt
index 832a257..7eb8ac9 100644
--- a/Documentation/trace-cmd-record.1.txt
+++ b/Documentation/trace-cmd-record.1.txt
@@ -240,6 +240,15 @@ OPTIONS
timestamp to gettimeofday which will allow wall time output from the
timestamps reading the created 'trace.dat' file.
+*--virt*::
+ This option is usded on a guest in a virtualization environment. If a host
+ is running "trace-cmd virt-server", this option is used to have the data
+ sent to the host with virtio-serial like *-N* option. (see also
+ trace-cmd-virt-server(1))
+
+ Note: This option is not supported with latency tracer plugins:
+ wakeup, wakeup_rt, irqsoff, preemptoff and preemptirqsoff
+
EXAMPLES
--------
@@ -302,7 +311,7 @@ SEE ALSO
--------
trace-cmd(1), trace-cmd-report(1), trace-cmd-start(1), trace-cmd-stop(1),
trace-cmd-extract(1), trace-cmd-reset(1), trace-cmd-split(1),
-trace-cmd-list(1), trace-cmd-listen(1)
+trace-cmd-list(1), trace-cmd-listen(1), trace-cmd-virt-server(1)
AUTHOR
------
diff --git a/trace-cmd.h b/trace-cmd.h
index b4c2267..5d895ff 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -251,7 +251,8 @@ void tracecmd_stat_cpu(struct trace_seq *s, int cpu);
long tracecmd_flush_recording(struct tracecmd_recorder *recorder);
/* for clients */
-int tracecmd_msg_connect_to_server(int fd);
+int tracecmd_msg_connect_to_server_nw(int fd);
+int tracecmd_msg_connect_to_server_virt(int fd);
int tracecmd_msg_metadata_send(int fd, char *buf, int size);
int tracecmd_msg_finish_sending_metadata(int fd);
void tracecmd_msg_send_close_msg();
diff --git a/trace-msg.c b/trace-msg.c
index 251e99c..cdeeed3 100644
--- a/trace-msg.c
+++ b/trace-msg.c
@@ -30,6 +30,7 @@
#include <stdio.h>
#include <unistd.h>
#include <arpa/inet.h>
+#include <sys/stat.h>
#include <sys/types.h>
#include <linux/types.h>
@@ -503,11 +504,12 @@ static int tracecmd_msg_wait_for_msg(int fd, struct tracecmd_msg **msg)
return 0;
}
-int tracecmd_msg_connect_to_server(int fd)
+static int tracecmd_msg_connect_to_server(int fd, bool nw)
{
struct tracecmd_msg *msg;
u32 reply_cmd, cmd;
int i, ret, cpus;
+ char buf[PATH_MAX];
/* connect to a server */
cmd = MSG_TCONNECT;
@@ -529,9 +531,24 @@ int tracecmd_msg_connect_to_server(int fd)
} while (reply_cmd != MSG_RINIT);
cpus = ntohl(msg->data.rinit.cpus);
- client_ports = malloc_or_die(sizeof(int) * cpus);
- for (i = 0; i < cpus; i++)
- client_ports[i] = ntohl(msg->data.rinit.port_array[i]);
+ if (nw) {
+ client_ports = malloc_or_die(sizeof(int) * cpus);
+ for (i = 0; i < cpus; i++)
+ client_ports[i] =
+ ntohl(msg->data.rinit.port_array[i]);
+ } else {
+ virt_sfds = malloc_or_die(sizeof(int) * cpus);
+
+ /* Open data paths of virtio-serial */
+ for (i = 0; i < cpus; i++) {
+ snprintf(buf, PATH_MAX, TRACE_PATH_CPU, i);
+ virt_sfds[i] = open(buf, O_WRONLY);
+ if (virt_sfds[i] < 0) {
+ warning("Cannot open %s", TRACE_PATH_CPU, i);
+ return -errno;
+ }
+ }
+ }
/* Next, send meta data */
send_metadata = true;
@@ -543,6 +560,16 @@ error:
return ret;
}
+int tracecmd_msg_connect_to_server_nw(int fd)
+{
+ return tracecmd_msg_connect_to_server(fd, true);
+}
+
+int tracecmd_msg_connect_to_server_virt(int fd)
+{
+ return tracecmd_msg_connect_to_server(fd, false);
+}
+
static bool process_option(struct tracecmd_msg_opt *opt)
{
/* currently the only option we have is to us TCP */
diff --git a/trace-msg.h b/trace-msg.h
index 9ec95e5..d1f7321 100644
--- a/trace-msg.h
+++ b/trace-msg.h
@@ -2,6 +2,9 @@
#define _TRACE_MSG_H_
#include <stdbool.h>
+#define VIRTIO_PORTS "/dev/virtio-ports/"
+#define AGENT_CTL_PATH VIRTIO_PORTS "agent-ctl-path"
+#define TRACE_PATH_CPU VIRTIO_PORTS "trace-path-cpu%d"
/* for both clients and server */
bool use_tcp;
@@ -11,6 +14,7 @@ int cpu_count;
unsigned int page_size;
int *client_ports;
bool send_metadata;
+int *virt_sfds;
/* for server */
bool done;
diff --git a/trace-record.c b/trace-record.c
index ef30e31..df9e786 100644
--- a/trace-record.c
+++ b/trace-record.c
@@ -80,6 +80,9 @@ static int sfd;
/* Max size to let a per cpu file get */
static int max_kb;
+struct tracecmd_output *virt_handle;
+static bool virt;
+
static int do_ptrace;
static int filter_task;
@@ -1576,6 +1579,9 @@ static int create_recorder(struct buffer_instance *instance, int cpu, int extrac
if (client_ports) {
connect_port(cpu);
recorder = tracecmd_create_recorder_fd(client_ports[cpu], cpu, recorder_flags);
+ } else if (virt_sfds) {
+ recorder = tracecmd_create_recorder_fd(virt_sfds[cpu], cpu,
+ recorder_flags);
} else {
file = get_temp_file(instance, cpu);
recorder = create_recorder_instance(instance, file, cpu);
@@ -1600,9 +1606,15 @@ static int create_recorder(struct buffer_instance *instance, int cpu, int extrac
exit(0);
}
-static void communicate_with_listener(int fd)
+static void communicate_with_listener_nw(int fd)
+{
+ if (tracecmd_msg_connect_to_server_nw(fd) < 0)
+ die("Cannot communicate with server");
+}
+
+static void communicate_with_listener_virt(int fd)
{
- if (tracecmd_msg_connect_to_server(fd) < 0)
+ if (tracecmd_msg_connect_to_server_virt(fd) < 0)
die("Cannot communicate with server");
}
@@ -1654,7 +1666,7 @@ static void setup_network(void)
freeaddrinfo(result);
- communicate_with_listener(sfd);
+ communicate_with_listener_nw(sfd);
/* Now create the handle through this socket */
handle = tracecmd_create_init_fd_glob(sfd, listed_events);
@@ -1663,6 +1675,21 @@ static void setup_network(void)
/* OK, we are all set, let'r rip! */
}
+static void setup_virtio(void)
+{
+ int fd;
+
+ fd = open(AGENT_CTL_PATH, O_RDWR);
+ if (fd < 0)
+ die("Cannot open %s", AGENT_CTL_PATH);
+
+ communicate_with_listener_virt(fd);
+
+ /* Now create the handle through this socket */
+ virt_handle = tracecmd_create_init_fd_glob(fd, listed_events);
+ tracecmd_msg_finish_sending_metadata(fd);
+}
+
static void finish_network(void)
{
tracecmd_msg_send_close_msg();
@@ -1670,6 +1697,13 @@ static void finish_network(void)
free(host);
}
+static void finish_virt(void)
+{
+ tracecmd_msg_send_close_msg();
+ free(virt_handle);
+ free(virt_sfds);
+}
+
static void start_threads(void)
{
struct buffer_instance *instance;
@@ -1677,6 +1711,8 @@ static void start_threads(void)
if (host)
setup_network();
+ else if (virt)
+ setup_virtio();
/* make a thread for every CPU we have */
pids = malloc_or_die(sizeof(*pids) * cpu_count * (buffers + 1));
@@ -1721,6 +1757,9 @@ static void record_data(char *date2ts, struct trace_seq *s)
if (host) {
finish_network();
return;
+ } else if (virt) {
+ finish_virt();
+ return;
}
if (latency)
@@ -2207,6 +2246,7 @@ static void record_all_events(void)
}
enum {
+ OPT_virt = 252,
OPT_nosplice = 253,
OPT_funcstack = 254,
OPT_date = 255,
@@ -2278,6 +2318,7 @@ void trace_record (int argc, char **argv)
{"date", no_argument, NULL, OPT_date},
{"func-stack", no_argument, NULL, OPT_funcstack},
{"nosplice", no_argument, NULL, OPT_nosplice},
+ {"virt", no_argument, NULL, OPT_virt},
{"help", no_argument, NULL, '?'},
{NULL, 0, NULL, 0}
};
@@ -2389,6 +2430,8 @@ void trace_record (int argc, char **argv)
case 'o':
if (host)
die("-o incompatible with -N");
+ if (virt)
+ die("-o incompatible with --virt");
if (!record && !extract)
die("start does not take output\n"
"Did you mean 'record'?");
@@ -2420,6 +2463,8 @@ void trace_record (int argc, char **argv)
case 'N':
if (!record)
die("-N only available with record");
+ if (virt)
+ die("-N incompatible with --virt");
if (output)
die("-N incompatible with -o");
host = optarg;
@@ -2432,6 +2477,8 @@ void trace_record (int argc, char **argv)
max_kb = atoi(optarg);
break;
case 't':
+ if (virt)
+ die("-t incompatible with --virt");
use_tcp = 1;
break;
case 'b':
@@ -2458,6 +2505,17 @@ void trace_record (int argc, char **argv)
case OPT_nosplice:
recorder_flags |= TRACECMD_RECORD_NOSPLICE;
break;
+ case OPT_virt:
+ if (!record)
+ die("--virt only available with record");
+ if (host)
+ die("--virt incompatible with -N");
+ if (output)
+ die("--virt incompatible with -o");
+ if (use_tcp)
+ die("--virt incompatible with -t");
+ virt = true;
+ break;
default:
usage(argv);
}
@@ -2533,6 +2591,8 @@ void trace_record (int argc, char **argv)
latency = 1;
if (host)
die("Network tracing not available with latency tracer plugins");
+ if (virt)
+ die("Virtio-trace not available with latency tracer plugins");
}
if (fset < 0 && (strcmp(plugin, "function") == 0 ||
strcmp(plugin, "function_graph") == 0))
--
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