@@ -275,8 +275,9 @@ struct tracecmd_output *tracecmd_get_output_handle_fd(int fd);
enum {
TRACECMD_RECORD_NOSPLICE = (1 << 0), /* Use read instead of splice */
- TRACECMD_RECORD_SNAPSHOT = (1 << 1), /* extract from snapshot */
+ TRACECMD_RECORD_SNAPSHOT = (1 << 1), /* Extract from snapshot */
TRACECMD_RECORD_BLOCK = (1 << 2), /* Block on splice write */
+ TRACECMD_RECORD_NOBRASS = (1 << 3), /* Splice directly without a brass pipe */
};
void tracecmd_free_recorder(struct tracecmd_recorder *recorder);
@@ -332,16 +333,16 @@ bool tracecmd_msg_done(struct tracecmd_msg_handle *msg_handle);
void tracecmd_msg_set_done(struct tracecmd_msg_handle *msg_handle);
int tracecmd_msg_send_trace_req(struct tracecmd_msg_handle *msg_handle,
- int argc, char **argv);
+ int argc, char **argv, bool use_fifos);
int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
- int *argc, char ***argv);
+ int *argc, char ***argv, bool *use_fifos);
int tracecmd_msg_send_trace_resp(struct tracecmd_msg_handle *msg_handle,
int nr_cpus, int page_size,
- unsigned int *ports);
+ unsigned int *ports, bool use_fifos);
int tracecmd_msg_recv_trace_resp(struct tracecmd_msg_handle *msg_handle,
int *nr_cpus, int *page_size,
- unsigned int **ports);
+ unsigned int **ports, bool *use_fifos);
/* --- Plugin handling --- */
extern struct tep_plugin_option trace_ftrace_options[];
@@ -156,6 +156,10 @@ static int msg_write(int fd, struct tracecmd_msg *msg)
return __do_write_check(fd, msg->buf, data_size);
}
+enum msg_trace_flags {
+ MSG_TRACE_USE_FIFOS = 1 << 0,
+};
+
static int make_tinit(struct tracecmd_msg_handle *msg_handle,
struct tracecmd_msg *msg)
{
@@ -807,7 +811,7 @@ int tracecmd_msg_wait_close_resp(struct tracecmd_msg_handle *msg_handle)
return tracecmd_msg_wait_for_cmd(msg_handle, MSG_CLOSE_RESP);
}
-static int make_trace_req(struct tracecmd_msg *msg, int argc, char **argv)
+static int make_trace_req(struct tracecmd_msg *msg, int argc, char **argv, bool use_fifos)
{
size_t args_size = 0;
char *p;
@@ -817,6 +821,7 @@ static int make_trace_req(struct tracecmd_msg *msg, int argc, char **argv)
args_size += strlen(argv[i]) + 1;
msg->hdr.size = htonl(ntohl(msg->hdr.size) + args_size);
+ msg->trace_req.flags = use_fifos ? htonl(MSG_TRACE_USE_FIFOS) : htonl(0);
msg->trace_req.argc = htonl(argc);
msg->buf = calloc(args_size, 1);
if (!msg->buf)
@@ -830,13 +835,13 @@ static int make_trace_req(struct tracecmd_msg *msg, int argc, char **argv)
}
int tracecmd_msg_send_trace_req(struct tracecmd_msg_handle *msg_handle,
- int argc, char **argv)
+ int argc, char **argv, bool use_fifos)
{
struct tracecmd_msg msg;
int ret;
tracecmd_msg_init(MSG_TRACE_REQ, &msg);
- ret = make_trace_req(&msg, argc, argv);
+ ret = make_trace_req(&msg, argc, argv, use_fifos);
if (ret < 0)
return ret;
@@ -849,7 +854,7 @@ int tracecmd_msg_send_trace_req(struct tracecmd_msg_handle *msg_handle,
* free(argv);
*/
int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
- int *argc, char ***argv)
+ int *argc, char ***argv, bool *use_fifos)
{
struct tracecmd_msg msg;
char *p, *buf_end, **args;
@@ -895,6 +900,7 @@ int tracecmd_msg_recv_trace_req(struct tracecmd_msg_handle *msg_handle,
*argc = nr_args;
*argv = args;
+ *use_fifos = ntohl(msg.trace_req.flags) & MSG_TRACE_USE_FIFOS;
/*
* On success we're passing msg.buf to the caller through argv[0] so we
@@ -914,8 +920,8 @@ out:
return ret;
}
-static int make_trace_resp(struct tracecmd_msg *msg,
- int page_size, int nr_cpus, unsigned int *ports)
+static int make_trace_resp(struct tracecmd_msg *msg, int page_size, int nr_cpus,
+ unsigned int *ports, bool use_fifos)
{
int data_size;
@@ -926,6 +932,7 @@ static int make_trace_resp(struct tracecmd_msg *msg,
write_uints(msg->buf, data_size, ports, nr_cpus);
msg->hdr.size = htonl(ntohl(msg->hdr.size) + data_size);
+ msg->trace_resp.flags = use_fifos ? htonl(MSG_TRACE_USE_FIFOS) : htonl(0);
msg->trace_resp.cpus = htonl(nr_cpus);
msg->trace_resp.page_size = htonl(page_size);
@@ -934,13 +941,13 @@ static int make_trace_resp(struct tracecmd_msg *msg,
int tracecmd_msg_send_trace_resp(struct tracecmd_msg_handle *msg_handle,
int nr_cpus, int page_size,
- unsigned int *ports)
+ unsigned int *ports, bool use_fifos)
{
struct tracecmd_msg msg;
int ret;
tracecmd_msg_init(MSG_TRACE_RESP, &msg);
- ret = make_trace_resp(&msg, page_size, nr_cpus, ports);
+ ret = make_trace_resp(&msg, page_size, nr_cpus, ports, use_fifos);
if (ret < 0)
return ret;
@@ -949,7 +956,7 @@ int tracecmd_msg_send_trace_resp(struct tracecmd_msg_handle *msg_handle,
int tracecmd_msg_recv_trace_resp(struct tracecmd_msg_handle *msg_handle,
int *nr_cpus, int *page_size,
- unsigned int **ports)
+ unsigned int **ports, bool *use_fifos)
{
struct tracecmd_msg msg;
char *p, *buf_end;
@@ -971,6 +978,7 @@ int tracecmd_msg_recv_trace_resp(struct tracecmd_msg_handle *msg_handle,
goto out;
}
+ *use_fifos = ntohl(msg.trace_resp.flags) & MSG_TRACE_USE_FIFOS;
*nr_cpus = ntohl(msg.trace_resp.cpus);
*page_size = ntohl(msg.trace_resp.page_size);
*ports = calloc(*nr_cpus, sizeof(**ports));
@@ -8,6 +8,7 @@
#include <stdlib.h>
#include <fcntl.h>
#include <time.h>
+#include <poll.h>
#include <unistd.h>
#include <errno.h>
@@ -26,6 +27,8 @@
# define SPLICE_F_GIFT 8
#endif
+#define POLL_TIMEOUT_MS 1000
+
struct tracecmd_recorder {
int fd;
int fd1;
@@ -40,6 +43,7 @@ struct tracecmd_recorder {
int pages;
int count;
unsigned fd_flags;
+ unsigned trace_fd_flags;
unsigned flags;
};
@@ -127,6 +131,8 @@ tracecmd_create_buffer_recorder_fd2(int fd, int fd2, int cpu, unsigned flags,
if (!(recorder->flags & TRACECMD_RECORD_BLOCK))
recorder->fd_flags |= SPLICE_F_NONBLOCK;
+ recorder->trace_fd_flags = SPLICE_F_MOVE;
+
/* Init to know what to free and release */
recorder->trace_fd = -1;
recorder->brass[0] = -1;
@@ -171,7 +177,8 @@ tracecmd_create_buffer_recorder_fd2(int fd, int fd2, int cpu, unsigned flags,
goto out_free;
}
- if ((recorder->flags & TRACECMD_RECORD_NOSPLICE) == 0) {
+ if (!(recorder->flags & (TRACECMD_RECORD_NOSPLICE |
+ TRACECMD_RECORD_NOBRASS))) {
ret = pipe(recorder->brass);
if (ret < 0)
goto out_free;
@@ -380,7 +387,7 @@ static long splice_data(struct tracecmd_recorder *recorder)
long ret;
read = splice(recorder->trace_fd, NULL, recorder->brass[1], NULL,
- recorder->pipe_size, SPLICE_F_MOVE);
+ recorder->pipe_size, recorder->trace_fd_flags);
if (read < 0) {
if (errno == EAGAIN || errno == EINTR || errno == ENOTCONN)
return 0;
@@ -409,6 +416,47 @@ static long splice_data(struct tracecmd_recorder *recorder)
return total_read;
}
+/*
+ * Returns -1 on error.
+ * or bytes of data read.
+ */
+static long direct_splice_data(struct tracecmd_recorder *recorder)
+{
+ struct pollfd pfd = {
+ .fd = recorder->trace_fd,
+ .events = POLLIN,
+ };
+ long read;
+ int ret;
+
+ /*
+ * splice(2) in Linux used to not check O_NONBLOCK flag of pipe file
+ * descriptors before [1]. To avoid getting blocked in the splice(2)
+ * call below after the user had requested to stop tracing, we poll(2)
+ * here. This poll() is not necessary on newer kernels.
+ *
+ * [1] https://github.com/torvalds/linux/commit/ee5e001196d1345b8fee25925ff5f1d67936081e
+ */
+ ret = poll(&pfd, 1, POLL_TIMEOUT_MS);
+ if (ret < 0)
+ return -1;
+
+ if (!(pfd.revents | POLLIN))
+ return 0;
+
+ read = splice(recorder->trace_fd, NULL, recorder->fd, NULL,
+ recorder->pipe_size, recorder->fd_flags);
+ if (read < 0) {
+ if (errno == EAGAIN || errno == EINTR || errno == ENOTCONN)
+ return 0;
+
+ warning("recorder error in splice input");
+ return -1;
+ }
+
+ return read;
+}
+
/*
* Returns -1 on error.
* or bytes of data read.
@@ -443,6 +491,17 @@ static long read_data(struct tracecmd_recorder *recorder)
return r;
}
+static long move_data(struct tracecmd_recorder *recorder)
+{
+ if (recorder->flags & TRACECMD_RECORD_NOSPLICE)
+ return read_data(recorder);
+
+ if (recorder->flags & TRACECMD_RECORD_NOBRASS)
+ return direct_splice_data(recorder);
+
+ return splice_data(recorder);
+}
+
static void set_nonblock(struct tracecmd_recorder *recorder)
{
long flags;
@@ -465,10 +524,7 @@ long tracecmd_flush_recording(struct tracecmd_recorder *recorder)
set_nonblock(recorder);
do {
- if (recorder->flags & TRACECMD_RECORD_NOSPLICE)
- ret = read_data(recorder);
- else
- ret = splice_data(recorder);
+ ret = move_data(recorder);
if (ret < 0)
return ret;
total += ret;
@@ -513,10 +569,7 @@ int tracecmd_start_recording(struct tracecmd_recorder *recorder, unsigned long s
read = 0;
do {
- if (recorder->flags & TRACECMD_RECORD_NOSPLICE)
- ret = read_data(recorder);
- else
- ret = splice_data(recorder);
+ ret = move_data(recorder);
if (ret < 0)
return ret;
read += ret;
@@ -17,6 +17,7 @@
#define GUEST_PIPE_NAME "trace-pipe-cpu"
#define GUEST_DIR_FMT "/var/lib/trace-cmd/virt/%s"
#define GUEST_FIFO_FMT GUEST_DIR_FMT "/" GUEST_PIPE_NAME "%d"
+#define VIRTIO_FIFO_FMT "/dev/virtio-ports/" GUEST_PIPE_NAME "%d"
extern int quiet;
@@ -99,7 +100,7 @@ void trace_usage(int argc, char **argv);
int trace_record_agent(struct tracecmd_msg_handle *msg_handle,
int cpus, int *fds,
- int argc, char **argv);
+ int argc, char **argv, bool use_fifos);
struct hook_list;
@@ -213,6 +214,7 @@ struct buffer_instance {
unsigned int cid;
unsigned int port;
int *fds;
+ bool use_fifos;
};
extern struct buffer_instance top_instance;
@@ -100,12 +100,38 @@ static void make_vsocks(int nr, int *fds, unsigned int *ports)
}
}
+static int open_agent_fifos(int nr_cpus, int *fds)
+{
+ char path[PATH_MAX];
+ int i, fd, ret;
+
+ for (i = 0; i < nr_cpus; i++) {
+ snprintf(path, sizeof(path), VIRTIO_FIFO_FMT, i);
+ fd = open(path, O_WRONLY);
+ if (fd < 0) {
+ ret = -errno;
+ goto cleanup;
+ }
+
+ fds[i] = fd;
+ }
+
+ return 0;
+
+cleanup:
+ while (--i >= 0)
+ close(fds[i]);
+
+ return ret;
+}
+
static void agent_handle(int sd, int nr_cpus, int page_size)
{
struct tracecmd_msg_handle *msg_handle;
unsigned int *ports;
char **argv = NULL;
int argc = 0;
+ bool use_fifos;
int *fds;
int ret;
@@ -118,17 +144,22 @@ static void agent_handle(int sd, int nr_cpus, int page_size)
if (!msg_handle)
die("Failed to allocate message handle");
- ret = tracecmd_msg_recv_trace_req(msg_handle, &argc, &argv);
+ ret = tracecmd_msg_recv_trace_req(msg_handle, &argc, &argv, &use_fifos);
if (ret < 0)
die("Failed to receive trace request");
- make_vsocks(nr_cpus, fds, ports);
+ if (use_fifos && open_agent_fifos(nr_cpus, fds))
+ use_fifos = false;
+
+ if (!use_fifos)
+ make_vsocks(nr_cpus, fds, ports);
- ret = tracecmd_msg_send_trace_resp(msg_handle, nr_cpus, page_size, ports);
+ ret = tracecmd_msg_send_trace_resp(msg_handle, nr_cpus, page_size,
+ ports, use_fifos);
if (ret < 0)
die("Failed to send trace response");
- trace_record_agent(msg_handle, nr_cpus, fds, argc, argv);
+ trace_record_agent(msg_handle, nr_cpus, fds, argc, argv, use_fifos);
free(argv[0]);
free(argv);
@@ -77,6 +77,8 @@ static int buffers;
/* Clear all function filters */
static int clear_function_filters;
+static bool no_fifos;
+
static char *host;
/* Max size to let a per cpu file get */
@@ -2972,12 +2974,17 @@ create_recorder_instance(struct buffer_instance *instance, const char *file, int
int fd;
unsigned int flags;
- fd = open_vsock(instance->cid, instance->client_ports[cpu]);
+ if (instance->use_fifos)
+ fd = instance->fds[cpu];
+ else
+ fd = open_vsock(instance->cid, instance->client_ports[cpu]);
if (fd < 0)
die("Failed to connect to agent");
flags = recorder_flags;
- if (!can_splice_read_vsock())
+ if (instance->use_fifos)
+ flags |= TRACECMD_RECORD_NOBRASS;
+ else if (!can_splice_read_vsock())
flags |= TRACECMD_RECORD_NOSPLICE;
return tracecmd_create_recorder_virt(file, cpu, flags, fd);
}
@@ -3032,10 +3039,14 @@ static int create_recorder(struct buffer_instance *instance, int cpu,
char *path = NULL;
int fd;
- if (is_agent(instance))
- fd = do_accept(instance->fds[cpu]);
- else
+ if (is_agent(instance)) {
+ if (instance->use_fifos)
+ fd = instance->fds[cpu];
+ else
+ fd = do_accept(instance->fds[cpu]);
+ } else {
fd = connect_port(host, instance->client_ports[cpu]);
+ }
if (fd < 0)
die("Failed connecting to client");
if (instance->name && !is_agent(instance))
@@ -3316,11 +3327,42 @@ static void finish_network(struct tracecmd_msg_handle *msg_handle)
free(host);
}
+static int open_guest_fifos(const char *guest, int **fds)
+{
+ char path[PATH_MAX];
+ int i, fd, flags;
+
+ for (i = 0; ; i++) {
+ snprintf(path, sizeof(path), GUEST_FIFO_FMT ".out", guest, i);
+
+ /* O_NONBLOCK so we don't wait for writers */
+ fd = open(path, O_RDONLY | O_NONBLOCK);
+ if (fd < 0)
+ break;
+
+ /* Success, now clear O_NONBLOCK */
+ flags = fcntl(fd, F_GETFL);
+ fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
+
+ *fds = realloc(*fds, i + 1);
+ (*fds)[i] = fd;
+ }
+
+ return i;
+}
+
static void connect_to_agent(struct buffer_instance *instance)
{
struct tracecmd_msg_handle *msg_handle;
- int sd, ret, nr_cpus, page_size;
+ int sd, ret, nr_fifos, nr_cpus, page_size;
unsigned int *ports;
+ int i, *fds = NULL;
+ bool use_fifos = false;
+
+ if (!no_fifos) {
+ nr_fifos = open_guest_fifos(instance->name, &fds);
+ use_fifos = nr_fifos > 0;
+ }
sd = open_vsock(instance->cid, instance->port);
if (sd < 0)
@@ -3331,15 +3373,33 @@ static void connect_to_agent(struct buffer_instance *instance)
if (!msg_handle)
die("Failed to allocate message handle");
- ret = tracecmd_msg_send_trace_req(msg_handle, instance->argc, instance->argv);
+ ret = tracecmd_msg_send_trace_req(msg_handle, instance->argc,
+ instance->argv, use_fifos);
if (ret < 0)
die("Failed to send trace request");
- ret = tracecmd_msg_recv_trace_resp(msg_handle, &nr_cpus, &page_size, &ports);
+ ret = tracecmd_msg_recv_trace_resp(msg_handle, &nr_cpus, &page_size,
+ &ports, &use_fifos);
if (ret < 0)
die("Failed to receive trace response");
- instance->client_ports = ports;
+ if (use_fifos) {
+ if (nr_cpus != nr_fifos) {
+ warning("number of FIFOs (%d) for guest %s differs "
+ "from number of virtual CPUs (%d)",
+ nr_fifos, instance->name, nr_cpus);
+ nr_cpus = nr_cpus < nr_fifos ? nr_cpus : nr_fifos;
+ }
+ free(ports);
+ instance->fds = fds;
+ } else {
+ for (i = 0; i < nr_fifos; i++)
+ close(fds[i]);
+ free(fds);
+ instance->client_ports = ports;
+ }
+
+ instance->use_fifos = use_fifos;
instance->cpu_count = nr_cpus;
/* the msg_handle now points to the guest fd */
@@ -4868,6 +4928,7 @@ enum {
OPT_funcstack = 254,
OPT_date = 255,
OPT_module = 256,
+ OPT_nofifos = 257,
};
void trace_stop(int argc, char **argv)
@@ -5138,6 +5199,7 @@ static void parse_record_options(int argc,
{"date", no_argument, NULL, OPT_date},
{"func-stack", no_argument, NULL, OPT_funcstack},
{"nosplice", no_argument, NULL, OPT_nosplice},
+ {"nofifos", no_argument, NULL, OPT_nofifos},
{"profile", no_argument, NULL, OPT_profile},
{"stderr", no_argument, NULL, OPT_stderr},
{"by-comm", no_argument, NULL, OPT_bycomm},
@@ -5429,6 +5491,9 @@ static void parse_record_options(int argc,
case OPT_nosplice:
recorder_flags |= TRACECMD_RECORD_NOSPLICE;
break;
+ case OPT_nofifos:
+ no_fifos = true;
+ break;
case OPT_profile:
handle_init = trace_init_profile;
ctx->instance->flags |= BUFFER_FL_PROFILE;
@@ -5836,7 +5901,8 @@ void trace_record(int argc, char **argv)
int trace_record_agent(struct tracecmd_msg_handle *msg_handle,
int cpus, int *fds,
- int argc, char **argv)
+ int argc, char **argv,
+ bool use_fifos)
{
struct common_record_context ctx;
char **argv_plus;
@@ -5862,6 +5928,7 @@ int trace_record_agent(struct tracecmd_msg_handle *msg_handle,
return -EINVAL;
ctx.instance->fds = fds;
+ ctx.instance->use_fifos = use_fifos;
ctx.instance->flags |= BUFFER_FL_AGENT;
ctx.instance->msg_handle = msg_handle;
msg_handle->version = V3_PROTOCOL;
Add FIFO transport for trace-cmd VM kernel tracing if guest FIFOs are available and attached to guest. We can also do a direct splice from the transport FIFO to the output file descriptor instead of two through an additional pipe buffer. This patch implements specialized version for tracecmd_recorder data transfer for this case. Signed-off-by: Slavomir Kaslev <kaslevs@vmware.com> --- include/trace-cmd/trace-cmd.h | 11 +++-- lib/trace-cmd/trace-msg.c | 26 ++++++---- lib/trace-cmd/trace-recorder.c | 73 ++++++++++++++++++++++++---- tracecmd/include/trace-local.h | 4 +- tracecmd/trace-agent.c | 39 +++++++++++++-- tracecmd/trace-record.c | 87 ++++++++++++++++++++++++++++++---- 6 files changed, 201 insertions(+), 39 deletions(-)