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oprofile: fix lost sample counter

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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>
This commit is contained in:
Robert Richter 2008-12-09 02:13:25 +01:00
parent 1d7503b5dc
commit 211117ff09
1 changed files with 53 additions and 30 deletions
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83
drivers/oprofile/cpu_buffer.c
View file

@ -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;
add_sample(cpu_buf, pc, 0);
if (add_sample(cpu_buf, pc, 0))
goto fail;
return;
fail:
cpu_buf->tracing = 0;
cpu_buf->backtrace_aborted++;
return;
}
/*