On 4/10/24 7:09 AM, Jiri Olsa wrote:
We have two printk tests reading trace_pipe in non blocking way,
with the very same code. Moving that in new read_trace_pipe_iter
function.
Current read_trace_pipe is used from sampless/bpf and needs to
do blocking read and printf of the trace_pipe data, using new
read_trace_pipe_iter to implement that.
Both printk tests do early checks for the number of found messages
and can bail earlier, but I did not find any speed difference w/o
that condition, so I did not complicate the change more for that.
Some of the samples/bpf programs use read_trace_pipe function,
so I kept that interface untouched. I did not see any issues with
affected samples/bpf programs other than there's slight change in
read_trace_pipe output. The current code uses puts that adds new
line after the printed string, so we would occasionally see extra
new line. With this patch we read output per lines, so there's no
need to use puts and we can use just printf instead without extra
new line.
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Ack with a nit below.
Acked-by: Yonghong Song <yonghong.song@xxxxxxxxx>
---
v2 changes:
- call read_trace_pipe_iter callback only in case there's new data
read from getline
.../selftests/bpf/prog_tests/trace_printk.c | 36 +++--------
.../selftests/bpf/prog_tests/trace_vprintk.c | 36 +++--------
tools/testing/selftests/bpf/trace_helpers.c | 63 ++++++++++++-------
tools/testing/selftests/bpf/trace_helpers.h | 2 +
4 files changed, 60 insertions(+), 77 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/trace_printk.c b/tools/testing/selftests/bpf/prog_tests/trace_printk.c
index 7b9124d506a5..e56e88596d64 100644
--- a/tools/testing/selftests/bpf/prog_tests/trace_printk.c
+++ b/tools/testing/selftests/bpf/prog_tests/trace_printk.c
@@ -5,18 +5,19 @@
#include "trace_printk.lskel.h"
-#define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe"
-#define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe"
#define SEARCHMSG "testing,testing"
+static void trace_pipe_cb(const char *str, void *data)
+{
+ if (strstr(str, SEARCHMSG) != NULL)
+ (*(int *)data)++;
+}
+
void serial_test_trace_printk(void)
{
struct trace_printk_lskel__bss *bss;
- int err = 0, iter = 0, found = 0;
struct trace_printk_lskel *skel;
- char *buf = NULL;
- FILE *fp = NULL;
- size_t buflen;
+ int err = 0, found = 0;
skel = trace_printk_lskel__open();
if (!ASSERT_OK_PTR(skel, "trace_printk__open"))
@@ -35,16 +36,6 @@ void serial_test_trace_printk(void)
if (!ASSERT_OK(err, "trace_printk__attach"))
goto cleanup;
- if (access(TRACEFS_PIPE, F_OK) == 0)
- fp = fopen(TRACEFS_PIPE, "r");
- else
- fp = fopen(DEBUGFS_PIPE, "r");
- if (!ASSERT_OK_PTR(fp, "fopen(TRACE_PIPE)"))
- goto cleanup;
-
- /* We do not want to wait forever if this test fails... */
- fcntl(fileno(fp), F_SETFL, O_NONBLOCK);
-
/* wait for tracepoint to trigger */
usleep(1);
trace_printk_lskel__detach(skel);
@@ -56,21 +47,12 @@ void serial_test_trace_printk(void)
goto cleanup;
/* verify our search string is in the trace buffer */
- while (getline(&buf, &buflen, fp) >= 0 || errno == EAGAIN) {
- if (strstr(buf, SEARCHMSG) != NULL)
- found++;
- if (found == bss->trace_printk_ran)
- break;
The above condition is not covered, but I think it is okay since the test
will run in serial mode.
- if (++iter > 1000)
- break;
- }
+ ASSERT_OK(read_trace_pipe_iter(trace_pipe_cb, &found, 1000),
+ "read_trace_pipe_iter");
if (!ASSERT_EQ(found, bss->trace_printk_ran, "found"))
goto cleanup;
cleanup:
trace_printk_lskel__destroy(skel);
- free(buf);
- if (fp)
- fclose(fp);
}
diff --git a/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c b/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c
index 44ea2fd88f4c..2af6a6f2096a 100644
--- a/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c
+++ b/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c
@@ -5,18 +5,19 @@
#include "trace_vprintk.lskel.h"
-#define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe"
-#define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe"
#define SEARCHMSG "1,2,3,4,5,6,7,8,9,10"
+static void trace_pipe_cb(const char *str, void *data)
+{
+ if (strstr(str, SEARCHMSG) != NULL)
+ (*(int *)data)++;
+}
+
void serial_test_trace_vprintk(void)
{
struct trace_vprintk_lskel__bss *bss;
- int err = 0, iter = 0, found = 0;
struct trace_vprintk_lskel *skel;
- char *buf = NULL;
- FILE *fp = NULL;
- size_t buflen;
+ int err = 0, found = 0;
skel = trace_vprintk_lskel__open_and_load();
if (!ASSERT_OK_PTR(skel, "trace_vprintk__open_and_load"))
@@ -28,16 +29,6 @@ void serial_test_trace_vprintk(void)
if (!ASSERT_OK(err, "trace_vprintk__attach"))
goto cleanup;
- if (access(TRACEFS_PIPE, F_OK) == 0)
- fp = fopen(TRACEFS_PIPE, "r");
- else
- fp = fopen(DEBUGFS_PIPE, "r");
- if (!ASSERT_OK_PTR(fp, "fopen(TRACE_PIPE)"))
- goto cleanup;
-
- /* We do not want to wait forever if this test fails... */
- fcntl(fileno(fp), F_SETFL, O_NONBLOCK);
-
/* wait for tracepoint to trigger */
usleep(1);
trace_vprintk_lskel__detach(skel);
@@ -49,14 +40,8 @@ void serial_test_trace_vprintk(void)
goto cleanup;
/* verify our search string is in the trace buffer */
- while (getline(&buf, &buflen, fp) >= 0 || errno == EAGAIN) {
- if (strstr(buf, SEARCHMSG) != NULL)
- found++;
- if (found == bss->trace_vprintk_ran)
- break;
- if (++iter > 1000)
- break;
- }
+ ASSERT_OK(read_trace_pipe_iter(trace_pipe_cb, &found, 1000),
+ "read_trace_pipe_iter");
if (!ASSERT_EQ(found, bss->trace_vprintk_ran, "found"))
goto cleanup;
@@ -66,7 +51,4 @@ void serial_test_trace_vprintk(void)
cleanup:
trace_vprintk_lskel__destroy(skel);
- free(buf);
- if (fp)
- fclose(fp);
}
[...]
ssize_t get_uprobe_offset(const void *addr)
{
size_t start, end, base;
@@ -413,3 +390,43 @@ int read_build_id(const char *path, char *build_id, size_t size)
close(fd);
return err;
}
+
+int read_trace_pipe_iter(void (*cb)(const char *str, void *data), void *data, int iter)
+{
+ size_t buflen, n;
+ char *buf = NULL;
+ FILE *fp = NULL;
+
+ if (access(TRACEFS_PIPE, F_OK) == 0)
+ fp = fopen(TRACEFS_PIPE, "r");
+ else
+ fp = fopen(DEBUGFS_PIPE, "r");
+ if (!fp)
+ return -1;
+
+ /* We do not want to wait forever when iter is specified. */
+ if (iter)
+ fcntl(fileno(fp), F_SETFL, O_NONBLOCK);
+
+ while ((n = getline(&buf, &buflen, fp) >= 0) || errno == EAGAIN) {
+ if (n > 0)
+ cb(buf, data);
+ if (iter && !(--iter))
"if (iter-- == 1)" should also work. But your code works too.
+ break;
+ }
+
+ free(buf);
+ if (fp)
+ fclose(fp);
+ return 0;
+}
+
[...]
