On Mon, 17 Aug 2020, Peter Xu wrote:
> Then they can be further used by other programs too.
>
> Two trivial things to mention.
>
> Firstly, move trace_marker out of enable_trace_mark(). No functional change.
>
> Secondly, remove the fileprefix setting in process_options(), because if
> tracelimit is non-zero, fileprefix will be after all replaced by a further call
> to get_debugfileprefix() in debugfs_prepare().
>
> Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
> ---
> src/cyclictest/cyclictest.c | 90 +------------------------------------
> src/include/rt-utils.h | 3 ++
> src/lib/rt-utils.c | 82 +++++++++++++++++++++++++++++++++
> 3 files changed, 86 insertions(+), 89 deletions(-)
>
> diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
> index eb61be3..dd41893 100644
> --- a/src/cyclictest/cyclictest.c
> +++ b/src/cyclictest/cyclictest.c
> @@ -219,8 +219,6 @@ static pthread_barrier_t align_barr;
> static pthread_barrier_t globalt_barr;
> static struct timespec globalt;
>
> -static char *procfileprefix = "/proc/sys/kernel/";
> -static char *fileprefix;
> static char fifopath[MAX_PATH];
> static char histfile[MAX_PATH];
>
> @@ -330,89 +328,6 @@ static inline int64_t calctime(struct timespec t)
> return time;
> }
>
> -static int trace_file_exists(char *name)
> -{
> - struct stat sbuf;
> - char *tracing_prefix = get_debugfileprefix();
> - char path[MAX_PATH];
> - strcat(strcpy(path, tracing_prefix), name);
> - return stat(path, &sbuf) ? 0 : 1;
> -}
> -
> -#define TRACEBUFSIZ 1024
> -static __thread char tracebuf[TRACEBUFSIZ];
> -
> -static void tracemark(char *fmt, ...) __attribute__((format(printf, 1, 2)));
> -static void tracemark(char *fmt, ...)
> -{
> - va_list ap;
> - int len;
> -
> - /* bail out if we're not tracing */
> - /* or if the kernel doesn't support trace_mark */
> - if (tracemark_fd < 0 || trace_fd < 0)
> - return;
> -
> - va_start(ap, fmt);
> - len = vsnprintf(tracebuf, TRACEBUFSIZ, fmt, ap);
> - va_end(ap);
> -
> - /* write the tracemark message */
> - write(tracemark_fd, tracebuf, len);
> -
> - /* now stop any trace */
> - write(trace_fd, "0\n", 2);
> -}
> -
> -static void open_tracemark_fd(void)
> -{
> - char path[MAX_PATH];
> -
> - /*
> - * open the tracemark file if it's not already open
> - */
> - if (tracemark_fd < 0) {
> - sprintf(path, "%s/%s", fileprefix, "trace_marker");
> - tracemark_fd = open(path, O_WRONLY);
> - if (tracemark_fd < 0) {
> - warn("unable to open trace_marker file: %s\n", path);
> - return;
> - }
> - }
> -
> - /*
> - * if we're not tracing and the tracing_on fd is not open,
> - * open the tracing_on file so that we can stop the trace
> - * if we hit a breaktrace threshold
> - */
> - if (trace_fd < 0) {
> - sprintf(path, "%s/%s", fileprefix, "tracing_on");
> - if ((trace_fd = open(path, O_WRONLY)) < 0)
> - warn("unable to open tracing_on file: %s\n", path);
> - }
> -}
> -
> -static void debugfs_prepare(void)
> -{
> - if (mount_debugfs(NULL))
> - fatal("could not mount debugfs");
> -
> - fileprefix = get_debugfileprefix();
> - if (!trace_file_exists("tracing_enabled") &&
> - !trace_file_exists("tracing_on"))
> - warn("tracing_enabled or tracing_on not found\n"
> - "debug fs not mounted");
> -}
> -
> -static void enable_trace_mark(void)
> -{
> - if (!trace_marker)
> - return;
> -
> - debugfs_prepare();
> - open_tracemark_fd();
> -}
> -
> /*
> * Raise the soft priority limit up to prio, if that is less than or equal
> * to the hard limit
> @@ -1498,9 +1413,6 @@ static void process_options (int argc, char *argv[], int max_cpus)
> "on this processor\n");
> }
>
> - if (tracelimit)
> - fileprefix = procfileprefix;
> -
> if (clocksel < 0 || clocksel > ARRAY_SIZE(clocksources))
> error = 1;
>
> @@ -2065,7 +1977,7 @@ int main(int argc, char **argv)
> /* use the /dev/cpu_dma_latency trick if it's there */
> set_latency_target();
>
> - if (tracelimit)
> + if (tracelimit && trace_marker)
> enable_trace_mark();
>
> if (check_timer())
> diff --git a/src/include/rt-utils.h b/src/include/rt-utils.h
> index 6ec2b20..51489b4 100644
> --- a/src/include/rt-utils.h
> +++ b/src/include/rt-utils.h
> @@ -27,4 +27,7 @@ pid_t gettid(void);
>
> int parse_time_string(char *val);
>
> +void enable_trace_mark(void);
> +void tracemark(char *fmt, ...) __attribute__((format(printf, 1, 2)));
> +
> #endif /* __RT_UTILS.H */
> diff --git a/src/lib/rt-utils.c b/src/lib/rt-utils.c
> index 1998a32..f786588 100644
> --- a/src/lib/rt-utils.c
> +++ b/src/lib/rt-utils.c
> @@ -24,7 +24,13 @@
> #include "rt-sched.h"
> #include "error.h"
>
> +#define TRACEBUFSIZ 1024
> +
> static char debugfileprefix[MAX_PATH];
> +static char *fileprefix;
> +static int trace_fd = -1;
> +static int tracemark_fd = -1;
> +static __thread char tracebuf[TRACEBUFSIZ];
>
> /*
> * Finds the tracing directory in a mounted debugfs
> @@ -355,3 +361,79 @@ int parse_time_string(char *val)
> }
> return t;
> }
> +
> +void open_tracemark_fd(void)
> +{
> + char path[MAX_PATH];
> +
> + /*
> + * open the tracemark file if it's not already open
> + */
> + if (tracemark_fd < 0) {
> + sprintf(path, "%s/%s", fileprefix, "trace_marker");
> + tracemark_fd = open(path, O_WRONLY);
> + if (tracemark_fd < 0) {
> + warn("unable to open trace_marker file: %s\n", path);
> + return;
> + }
> + }
> +
> + /*
> + * if we're not tracing and the tracing_on fd is not open,
> + * open the tracing_on file so that we can stop the trace
> + * if we hit a breaktrace threshold
> + */
> + if (trace_fd < 0) {
> + sprintf(path, "%s/%s", fileprefix, "tracing_on");
> + if ((trace_fd = open(path, O_WRONLY)) < 0)
> + warn("unable to open tracing_on file: %s\n", path);
> + }
> +}
> +
> +int trace_file_exists(char *name)
> +{
> + struct stat sbuf;
> + char *tracing_prefix = get_debugfileprefix();
> + char path[MAX_PATH];
> + strcat(strcpy(path, tracing_prefix), name);
> + return stat(path, &sbuf) ? 0 : 1;
> +}
> +
> +void debugfs_prepare(void)
> +{
> + if (mount_debugfs(NULL))
> + fatal("could not mount debugfs");
> +
> + fileprefix = get_debugfileprefix();
> + if (!trace_file_exists("tracing_enabled") &&
> + !trace_file_exists("tracing_on"))
> + warn("tracing_enabled or tracing_on not found\n"
> + "debug fs not mounted");
> +}
> +
> +void tracemark(char *fmt, ...)
> +{
> + va_list ap;
> + int len;
> +
> + /* bail out if we're not tracing */
> + /* or if the kernel doesn't support trace_mark */
> + if (tracemark_fd < 0 || trace_fd < 0)
> + return;
> +
> + va_start(ap, fmt);
> + len = vsnprintf(tracebuf, TRACEBUFSIZ, fmt, ap);
> + va_end(ap);
> +
> + /* write the tracemark message */
> + write(tracemark_fd, tracebuf, len);
> +
> + /* now stop any trace */
> + write(trace_fd, "0\n", 2);
> +}
> +
> +void enable_trace_mark(void)
> +{
> + debugfs_prepare();
> + open_tracemark_fd();
> +}
> --
> 2.26.2
>
>
Signed-off-by: John Kacur <jkacur@xxxxxxxxxx>
