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authorRobert Richter <robert.richter@amd.com>2008-12-09 02:13:25 +0100
committerRobert Richter <robert.richter@amd.com>2008-12-10 20:25:15 +0100
commit211117ff09b7d81d91b7857651587128ed8b13d9 (patch)
tree21145ea0cddbc3de803fd8621631e46b7c628057 /drivers/oprofile/cpu_buffer.c
parent1d7503b5dccf2b95babca050e4960e10d2633f2b (diff)
oprofile: fix lost sample counter
The number of lost samples could be greater than the number of received samples. This patches fixes this. The implementation introduces return values for add_sample() and add_code(). Signed-off-by: Robert Richter <robert.richter@amd.com>
Diffstat (limited to 'drivers/oprofile/cpu_buffer.c')
-rw-r--r--drivers/oprofile/cpu_buffer.c83
1 files changed, 53 insertions, 30 deletions
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index 7f7fc958297..61090969158 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -145,32 +145,31 @@ void end_cpu_work(void)
flush_scheduled_work();
}
-static inline void
+static inline int
add_sample(struct oprofile_cpu_buffer *cpu_buf,
unsigned long pc, unsigned long event)
{
struct op_entry entry;
+ int ret;
- if (cpu_buffer_write_entry(&entry))
- goto Error;
+ ret = cpu_buffer_write_entry(&entry);
+ if (ret)
+ return ret;
entry.sample->eip = pc;
entry.sample->event = event;
- if (cpu_buffer_write_commit(&entry))
- goto Error;
+ ret = cpu_buffer_write_commit(&entry);
+ if (ret)
+ return ret;
- return;
-
-Error:
- cpu_buf->sample_lost_overflow++;
- return;
+ return 0;
}
-static inline void
+static inline int
add_code(struct oprofile_cpu_buffer *buffer, unsigned long value)
{
- add_sample(buffer, ESCAPE_CODE, value);
+ return add_sample(buffer, ESCAPE_CODE, value);
}
/* This must be safe from any context. It's safe writing here
@@ -201,17 +200,25 @@ static int log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc,
/* notice a switch from user->kernel or vice versa */
if (cpu_buf->last_is_kernel != is_kernel) {
cpu_buf->last_is_kernel = is_kernel;
- add_code(cpu_buf, is_kernel);
+ if (add_code(cpu_buf, is_kernel))
+ goto fail;
}
/* notice a task switch */
if (cpu_buf->last_task != task) {
cpu_buf->last_task = task;
- add_code(cpu_buf, (unsigned long)task);
+ if (add_code(cpu_buf, (unsigned long)task))
+ goto fail;
}
- add_sample(cpu_buf, pc, event);
+ if (add_sample(cpu_buf, pc, event))
+ goto fail;
+
return 1;
+
+fail:
+ cpu_buf->sample_lost_overflow++;
+ return 0;
}
static int oprofile_begin_trace(struct oprofile_cpu_buffer *cpu_buf)
@@ -266,37 +273,49 @@ void oprofile_add_ibs_sample(struct pt_regs * const regs,
int is_kernel = !user_mode(regs);
struct oprofile_cpu_buffer *cpu_buf = &__get_cpu_var(cpu_buffer);
struct task_struct *task;
+ int fail = 0;
cpu_buf->sample_received++;
/* notice a switch from user->kernel or vice versa */
if (cpu_buf->last_is_kernel != is_kernel) {
+ if (add_code(cpu_buf, is_kernel))
+ goto fail;
cpu_buf->last_is_kernel = is_kernel;
- add_code(cpu_buf, is_kernel);
}
/* notice a task switch */
if (!is_kernel) {
task = current;
if (cpu_buf->last_task != task) {
+ if (add_code(cpu_buf, (unsigned long)task))
+ goto fail;
cpu_buf->last_task = task;
- add_code(cpu_buf, (unsigned long)task);
}
}
- add_code(cpu_buf, ibs_code);
- add_sample(cpu_buf, ibs_sample[0], ibs_sample[1]);
- add_sample(cpu_buf, ibs_sample[2], ibs_sample[3]);
- add_sample(cpu_buf, ibs_sample[4], ibs_sample[5]);
+ fail = fail || add_code(cpu_buf, ibs_code);
+ fail = fail || add_sample(cpu_buf, ibs_sample[0], ibs_sample[1]);
+ fail = fail || add_sample(cpu_buf, ibs_sample[2], ibs_sample[3]);
+ fail = fail || add_sample(cpu_buf, ibs_sample[4], ibs_sample[5]);
if (ibs_code == IBS_OP_BEGIN) {
- add_sample(cpu_buf, ibs_sample[6], ibs_sample[7]);
- add_sample(cpu_buf, ibs_sample[8], ibs_sample[9]);
- add_sample(cpu_buf, ibs_sample[10], ibs_sample[11]);
+ fail = fail || add_sample(cpu_buf, ibs_sample[6], ibs_sample[7]);
+ fail = fail || add_sample(cpu_buf, ibs_sample[8], ibs_sample[9]);
+ fail = fail || add_sample(cpu_buf, ibs_sample[10], ibs_sample[11]);
}
+ if (fail)
+ goto fail;
+
if (backtrace_depth)
oprofile_ops.backtrace(regs, backtrace_depth);
+
+ return;
+
+fail:
+ cpu_buf->sample_lost_overflow++;
+ return;
}
#endif
@@ -318,13 +337,17 @@ void oprofile_add_trace(unsigned long pc)
* broken frame can give an eip with the same value as an
* escape code, abort the trace if we get it
*/
- if (pc == ESCAPE_CODE) {
- cpu_buf->tracing = 0;
- cpu_buf->backtrace_aborted++;
- return;
- }
+ if (pc == ESCAPE_CODE)
+ goto fail;
+
+ if (add_sample(cpu_buf, pc, 0))
+ goto fail;
- add_sample(cpu_buf, pc, 0);
+ return;
+fail:
+ cpu_buf->tracing = 0;
+ cpu_buf->backtrace_aborted++;
+ return;
}
/*