[PATCH] tools/intel_guc_logger: Utility for capturing GuC firmware logs in a file

* [PATCH] tools/intel_guc_logger: Utility for capturing GuC firmware logs in a file
@ 2016-09-06 10:43 akash.goel
  2016-09-06 13:17 ` Tvrtko Ursulin
  0 siblings, 1 reply; 17+ messages in thread
From: akash.goel @ 2016-09-06 10:43 UTC (permalink / raw)
  To: intel-gfx; +Cc: Akash Goel

From: Akash Goel <akash.goel@intel.com>

This patch provides a test utility which helps capture GuC firmware logs and
then dump them to file.
The logs are pulled from a debugfs file '/sys/kernel/debug/dri/guc_log' and
stored into a file '/tmp/guc_log_dump.dat', the name of the output file can
be changed through a command line argument.

The utility goes into an infinite loop where it waits for the arrival of new
logs and as soon as new set of logs are produced it captures them in its local
buffer which is then flushed out to the file on disk.
Any time when logging needs to be ended, User can stop this utility (CTRL+C).

Before entering into a loop, it first discards whatever logs are present in
the debugfs file.
This way User can first launch this utility and then start a workload/activity
for which GuC firmware logs are to be actually captured and keep running the
utility for as long as its needed, like once the workload is over this utility
can be forcefully stopped.

If the logging wasn't enabled on GuC side by the Driver at boot time, utility
will first enable the logging and later on when it is stopped (CTRL+C) it will
also pause the logging on GuC side.

Signed-off-by: Akash Goel <akash.goel@intel.com>
---
 tools/Makefile.sources   |   1 +
 tools/intel_guc_logger.c | 441 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 442 insertions(+)
 create mode 100644 tools/intel_guc_logger.c

diff --git a/tools/Makefile.sources b/tools/Makefile.sources
index 2bb6c8e..be58871 100644
--- a/tools/Makefile.sources
+++ b/tools/Makefile.sources
@@ -19,6 +19,7 @@ tools_prog_lists =		\
 	intel_gpu_time		\
 	intel_gpu_top		\
 	intel_gtt		\
+	intel_guc_logger        \
 	intel_infoframes	\
 	intel_l3_parity		\
 	intel_lid		\
diff --git a/tools/intel_guc_logger.c b/tools/intel_guc_logger.c
new file mode 100644
index 0000000..92172fa
--- /dev/null
+++ b/tools/intel_guc_logger.c
@@ -0,0 +1,441 @@
+
+#define _GNU_SOURCE  /* For using O_DIRECT */
+#include <inttypes.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <sys/ioctl.h>
+#include <string.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/poll.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/syscall.h>
+#include <sys/mman.h>
+#include <assert.h>
+#include <pthread.h>
+
+#include "igt.h"
+
+#define MB(x) ((uint64_t)(x) * 1024 * 1024)
+#ifndef PAGE_SIZE
+  #define PAGE_SIZE 4096
+#endif
+#define SUBBUF_SIZE (19*PAGE_SIZE)
+/* Need large buffering from logger side to hide the DISK IO latency, Driver
+ * can only store 8 snapshots of GuC log buffer in relay.
+ */
+#define NUM_SUBBUFS 100
+
+#define RELAY_FILE_NAME  "guc_log"
+#define CONTROL_FILE_NAME "i915_guc_log_control"
+
+char *read_buffer;
+char *out_filename;
+int poll_timeout = 2; /* by default 2ms timeout */
+pthread_mutex_t mutex;
+pthread_t flush_thread;
+int verbosity_level = 3; /* by default capture logs at max verbosity */
+uint32_t produced, consumed;
+uint64_t total_bytes_written;
+int num_buffers = NUM_SUBBUFS;
+int relay_fd, outfile_fd = -1;
+bool stop_logging, discard_oldlogs;
+uint32_t test_duration, max_filesize;
+pthread_cond_t underflow_cond, overflow_cond;
+
+static void guc_log_control(bool enable_logging)
+{
+	int control_fd;
+	char data[19];
+	uint64_t val;
+	int ret;
+
+	control_fd = igt_debugfs_open(CONTROL_FILE_NAME, O_WRONLY);
+	if (control_fd < 0)
+		igt_assert_f(0, "Couldn't open the guc log control file");
+
+	val = enable_logging ? ((verbosity_level << 4) | 0x1) : 0;
+
+	snprintf(data, sizeof(data), "0x%" PRIx64, val);
+	ret = write(control_fd, data, strlen(data) + 1);
+	if (ret < 0)
+		igt_assert_f(0, "Couldn't write to the log control file");
+
+	close(control_fd);
+}
+
+static void int_sig_handler(int sig)
+{
+	igt_info("Received signal %d\n", sig);
+
+	stop_logging = true;
+}
+
+static void pull_leftover_data(void)
+{
+	unsigned int bytes_read = 0;
+	int ret;
+
+	while (1) {
+		/* Read the logs from relay buffer */
+		ret = read(relay_fd, read_buffer, SUBBUF_SIZE);
+		if (!ret)
+			break;
+		else if (ret < 0)
+			igt_assert_f(0, "Failed to read from the guc log file");
+		else if (ret < SUBBUF_SIZE)
+			igt_assert_f(0, "invalid read from relay file");
+
+		bytes_read += ret;
+
+		if (outfile_fd > 0) {
+			ret = write(outfile_fd, read_buffer, SUBBUF_SIZE);
+			if (ret < 0)
+				igt_assert_f(0, "Couldn't dump the logs in a file");
+			total_bytes_written += ret;
+		}
+	};
+
+	igt_debug("%u bytes flushed\n", bytes_read);
+}
+
+static int num_filled_bufs(void)
+{
+	return (produced - consumed);
+}
+
+static void pull_data(void)
+{
+	char *ptr;
+	int ret;
+
+	pthread_mutex_lock(&mutex);
+	while (num_filled_bufs() >= num_buffers) {
+		igt_debug("overflow, will wait, produced %u, consumed %u\n", produced, consumed);
+		/* Stall the main thread in case of overflow, as there are no
+		 * buffers available to store the new logs, otherwise there
+		 * could be corruption if both threads work on the same buffer.
+		 */
+		pthread_cond_wait(&overflow_cond, &mutex);
+	};
+	pthread_mutex_unlock(&mutex);
+
+	ptr = read_buffer + (produced % num_buffers) * SUBBUF_SIZE;
+
+	/* Read the logs from relay buffer */
+	ret = read(relay_fd, ptr, SUBBUF_SIZE);
+	if (ret < 0)
+		igt_assert_f(0, "Failed to read from the guc log file");
+	else if (ret && (ret < SUBBUF_SIZE))
+		igt_assert_f(0, "invalid read from relay file");
+
+	pthread_mutex_lock(&mutex);
+	if (ret) {
+		produced++;
+		pthread_cond_signal(&underflow_cond);
+	}
+	pthread_mutex_unlock(&mutex);
+}
+
+static void *flusher(void *arg)
+{
+	char *ptr;
+	int ret;
+
+	igt_debug("Execution started of flusher thread\n");
+
+	do {
+		pthread_mutex_lock(&mutex);
+		while (!num_filled_bufs()) {
+			/* Exit only after completing the flush of all the filled
+			 * buffers as User would expect that all logs captured up
+			 * till the point of interruption/exit are written out to
+			 * the disk file.
+			 */
+			if (stop_logging) {
+				igt_debug("flusher to exit now\n");
+				pthread_mutex_unlock(&mutex);
+				return NULL;
+			}
+			pthread_cond_wait(&underflow_cond, &mutex);
+		};
+		pthread_mutex_unlock(&mutex);
+
+		ptr = read_buffer + (consumed % num_buffers) * SUBBUF_SIZE;
+
+		ret = write(outfile_fd, ptr, SUBBUF_SIZE);
+		if (ret < 0)
+			igt_assert_f(0, "Couldn't dump the logs in a file");
+
+		total_bytes_written += ret;
+		if (max_filesize && (total_bytes_written > MB(max_filesize))) {
+			igt_debug("Reached the target of %" PRIu64 " bytes\n", MB(max_filesize));
+			stop_logging = true;
+		}
+
+		pthread_mutex_lock(&mutex);
+		consumed++;
+		pthread_cond_signal(&overflow_cond);
+		pthread_mutex_unlock(&mutex);
+	} while(1);
+
+	return NULL;
+}
+
+static void init_flusher_thread(void)
+{
+	struct sched_param	thread_sched;
+	pthread_attr_t		p_attr;
+
+	pthread_cond_init(&underflow_cond, NULL);
+	pthread_cond_init(&overflow_cond, NULL);
+	pthread_mutex_init(&mutex, NULL);
+
+	if (pthread_attr_init(&p_attr))
+		igt_assert_f(0, "Error obtaining default thread attributes");
+
+	if (pthread_attr_setinheritsched(&p_attr, PTHREAD_EXPLICIT_SCHED))
+		igt_assert_f(0, "Couldn't set inheritsched");
+
+	if (pthread_attr_setschedpolicy(&p_attr, SCHED_RR))
+		igt_assert_f(0, "Couldn't set thread scheduling policy");
+
+	/* Keep the flusher task also at rt priority, so that it doesn't get
+	 * too late in flushing the collected logs in local buffers to the disk,
+	 * and so main thread always have spare buffers to collect the logs.
+	 */
+	thread_sched.sched_priority = 5;
+	if (pthread_attr_setschedparam(&p_attr, &thread_sched))
+		igt_assert_f(0, "Couldn't set thread priority");
+
+	if (pthread_create(&flush_thread, &p_attr, flusher, NULL))
+		igt_assert_f(0, "thread creation failed");
+
+	if (pthread_attr_destroy(&p_attr))
+		igt_assert_f(0, "Error destroying thread attributes");
+}
+
+static void open_relay_file(void)
+{
+	relay_fd = igt_debugfs_open(RELAY_FILE_NAME, O_RDONLY);
+	if (relay_fd < 0)
+		igt_assert_f(0, "Couldn't open the guc log file");
+
+	/* Purge the old/boot-time logs from the relay buffer.
+	 * This is more for Val team's requirement, where they have to first
+	 * purge the existing logs before starting the tests for which the logs
+	 * are actually needed. After this logger will enter into a loop and
+	 * wait for the new data, at that point benchmark can be launched from
+	 * a different shell.
+	 */
+	if (discard_oldlogs)
+		pull_leftover_data();
+}
+
+static void open_output_file(void)
+{
+	char *filename;
+
+	if (asprintf(&filename, "/tmp/%s", out_filename ? : "guc_log_dump.dat") < 0)
+		igt_assert_f(0, "Couldn't allocate the filename");
+
+	/* Use Direct IO mode for the output file, as the data written is not
+	 * supposed to be accessed again, this saves a copy of data from App's
+	 * buffer to kernel buffer (Page cache). Due to no buffering on kernel
+	 * side, data is flushed out to disk faster and more buffering can be
+	 * done on the logger side to hide the disk IO latency.
+	 */
+	outfile_fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC | O_DIRECT, 0444);
+	if (outfile_fd < 0)
+		igt_assert_f(0, "Couldn't open the output file");
+
+	free(out_filename);
+	free(filename);
+}
+
+static void init_main_thread(void)
+{
+	struct sched_param	thread_sched;
+	/* Run the main thread at highest priority to ensure that it always
+	 * gets woken-up at earliest on arrival of new data and so is always
+	 * ready to pull the logs, otherwise there could be loss logs if
+	 * GuC firmware is generating logs at a very high rate.
+	 */
+	thread_sched.sched_priority = 1;
+	if (sched_setscheduler(getpid(), SCHED_FIFO, &thread_sched))
+		igt_assert_f(0, "Couldn't set the priority");
+
+	if (signal(SIGINT, int_sig_handler) == SIG_ERR)
+		igt_assert_f(0, "SIGINT handler registration failed");
+
+	/* Need an aligned pointer for direct IO */
+	if (posix_memalign((void **)&read_buffer, PAGE_SIZE, num_buffers * SUBBUF_SIZE))
+		igt_assert_f(0, "Couldn't allocate the read buffer");
+
+	/* Keep the pages locked in RAM, avoid page fault overhead */
+	if (mlock(read_buffer, num_buffers * SUBBUF_SIZE))
+		igt_assert_f(0, "Failed to lock memory");
+
+	/* Enable the logging, it may not have been enabled from boot and so
+	 * the relay file also wouldn't have been created.
+	 */
+	guc_log_control(true);
+
+	open_relay_file();
+	open_output_file();
+}
+
+static int parse_options(int opt, int opt_index, void *data)
+{
+	igt_debug("opt %c optarg %s\n", opt, optarg);
+
+	switch(opt) {
+	case 'v':
+		verbosity_level = atoi(optarg);
+		if (verbosity_level < 0)
+			verbosity_level = 0;
+		else if (verbosity_level > 3)
+			verbosity_level = 3;
+
+		igt_debug("verbosity level to be used is %d\n", verbosity_level);
+		break;
+	case 'o':
+		if (asprintf(&out_filename, "%s", optarg) < 0)
+			igt_assert_f(0, "Couldn't allocate the o/p filename");
+		igt_debug("logs to be stored in file /tmp/%s\n", out_filename);
+		break;
+	case 'b':
+		num_buffers = atoi(optarg);
+		if (num_buffers == 0)
+			num_buffers = NUM_SUBBUFS;
+		igt_debug("number of buffers to be used is %d\n", num_buffers);
+		break;
+	case 't':
+		test_duration = atoi(optarg);
+		if (test_duration > 0)
+			igt_debug("logger to run for %d seconds\n", test_duration);
+		break;
+	case 'p':
+		poll_timeout = atoi(optarg);
+		if (poll_timeout == 0)
+			poll_timeout = 2; /* at least use 2ms poll timeout */
+		if (poll_timeout > 0)
+			igt_debug("polling to be done with %d milli seconds timeout\n", poll_timeout);
+		break;
+	case 's':
+		max_filesize = atoi(optarg);
+		if (max_filesize > 0)
+			igt_debug("max allowed size of the output file is %d MBs\n", max_filesize);
+		break;
+	case 'd':
+		discard_oldlogs = true;
+		igt_debug("old/boot-time logs will be discarded\n");
+		break;
+	}
+
+	return 0;
+}
+
+static void process_command_line(int argc, char **argv)
+{
+	static struct option long_options[] = {
+		{"verbosity", required_argument, 0, 'v'},
+		{"outputfilename", required_argument, 0, 'o'},
+		{"buffers", required_argument, 0, 'b'},
+		{"testduration", required_argument, 0, 't'},
+		{"polltimeout", required_argument, 0, 'p'},
+		{"size", required_argument, 0, 's'},
+		{"discard", no_argument, 0, 'd'},
+		{ 0, 0, 0, 0 }
+	};
+
+	const char *help =
+		"  -v --verbosity=level   verbosity level of GuC logging (0-3)\n"
+		"  -o --outfile=name      name of the output file in /tmp directory, where logs will be stored\n"
+		"  -b --buffers=num       number of buffers to be maintained on logger side for storing logs\n"
+		"  -t --testduration=sec  max duration in seconds for which the logger should run, 0 == forever\n"
+		"  -p --polltimeout=ms    polling timeout in ms, -1 == indefinite wait for the new data\n"
+		"  -s --size=MB           max size of output file in MBs after which logging will be stopped, 0 == no limit\n"
+		"  -d --discard           discard the old/boot-time logs before entering into the capture loop\n";
+
+	igt_simple_init_parse_opts(&argc, argv, "v:o:b:t:p:s:d", long_options,
+				   help, parse_options, NULL);
+}
+
+int main(int argc, char **argv)
+{
+	struct pollfd relay_poll_fd;
+	struct timespec start={};
+	int nfds;
+	int ret;
+
+	process_command_line(argc, argv);
+
+	init_main_thread();
+
+	/* Use a separate thread for flushing the logs to a file on disk.
+	 * Main thread will buffer the data from relay file in its pool of
+	 * buffers and other thread will flush the data to disk in background.
+	 * This is needed, albeit by default data is written out to disk in
+	 * async mode, as when there are too many dirty pages in the RAM,
+	 * (/proc/sys/vm/dirty_ratio), kernel starts blocking the processes
+	 * doing the file writes.
+	 */
+	init_flusher_thread();
+
+	relay_poll_fd.fd = relay_fd;
+	relay_poll_fd.events = POLLIN;
+	relay_poll_fd.revents = 0;
+
+	nfds = 1; /* only one fd to poll */
+
+	while (!stop_logging)
+	{
+		if (test_duration && (igt_seconds_elapsed(&start) > test_duration)) {
+			igt_debug("Ran for stipulated %d seconds, exit now\n", test_duration);
+			stop_logging = true;
+			break;
+		}
+
+		/* Wait/poll for the new data to be available, relay doesn't
+		 * provide a blocking read.
+		 * Need to do polling with a timeout instead of indefinite wait,
+		 * to avoid relying on relay for the wakeup, as relay does wakeup
+		 * in a deferred manner on jiffies granularity by scheduling a
+		 * timer and moreover that timer is re-scheduled on every newly
+		 * produced buffer so timer keeps getting pushed out if there
+		 * are multiple flush interrupts in a very quick succession (less
+		 * than a jiffy gap between 2 flush interrupts) and relay runs
+		 * out of sub buffers to store the new logs.
+		 */
+		ret = poll(&relay_poll_fd, nfds, poll_timeout);
+		if (ret < 0) {
+			if (errno == EINTR)
+				break;
+			else
+				igt_assert_f(0, "poll call failed");
+		}
+
+		/* No data available yet, poll again, hopefully new data is round the corner */
+		if (!relay_poll_fd.revents)
+			continue;
+
+		pull_data();
+	}
+
+	/* Pause logging on the GuC side*/
+	guc_log_control(false);
+	pthread_cond_signal(&underflow_cond);
+	pthread_join(flush_thread, NULL);
+	pull_leftover_data();
+	igt_info("total_bytes_written %" PRIu64 "\n", total_bytes_written);
+
+	free(read_buffer);
+	close(relay_fd);
+	close(outfile_fd);
+	igt_exit();
+}
-- 
1.9.2

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