On Tue, 19 Mar 2019 at 04:00, Suzuki K Poulose suzuki.poulose@arm.com wrote:
Hi Mathieu,
On 06/03/2019 22:57, Mathieu Poirier wrote:
In preparation to support CPU-wide trace scenarios, add the notion of process ID to ETR devices so that memory buffers can be shared between events.
The PID only matters to the perf buffers. And etr_buf is really a representation of the ETR Hw buffer and I prefer to keep it that way. Please could we have all the "perf" related book keeping in the etr_perf_buf, which holds the perf session specific data ?
From a quick look at the code it might streamline the allocation/free
process. I'll let you know if I run into problems but for now I'm pretty sure it is possible.
As for enforcing the FLAT mode in the later series, we don't necessarily need to force it for double buffering. Even our SG mode uses double buffering. Even otherwise, we may be able to force a mode, than passing down perf specific data to the generic ETR buffer.
The patches to force the flat mode was to make sure things are covered when the ETR improves and we are able to use the perf ring buffer properly. I'm happy to drop them (I never really liked them).
Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org
.../hwtracing/coresight/coresight-tmc-etr.c | 26 +++++++++++++++---- drivers/hwtracing/coresight/coresight-tmc.h | 6 +++++ 2 files changed, 27 insertions(+), 5 deletions(-)
...
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index 487c53701e9c..d3657acb6cbf 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -9,6 +9,8 @@
#include <linux/dma-mapping.h> #include <linux/miscdevice.h> +#include <linux/refcount.h> +#include <linux/types.h>
#define TMC_RSZ 0x004 #define TMC_STS 0x00c @@ -133,6 +135,8 @@ struct etr_buf_operations;
/**
- struct etr_buf - Details of the buffer used by ETR
- @pid : The pid this etr_buf belongs to.
- @refcount : Number of sources currently using this etr_buf.
- @mode : Mode of the ETR buffer, contiguous, Scatter Gather etc.
- @full : Trace data overflow
- @size : Size of the buffer.
@@ -143,6 +147,8 @@ struct etr_buf_operations;
- @private : Backend specific information for the buf
*/ struct etr_buf {
pid_t pid;refcount_t refcount;As mentioned above, those are better suited for etr_perf_buf.
Thoughts ?
Suzuki