[dpdk-dev] [PATCH v3 0/4] introduce global debug flag

[Lukasz Wojciechowski]

This set of patches introduces a global rte_debug flag for dpdk.
This will allow easy switch to debug build configuration using a single
flag. In the debug mode a RTE_DEBUG macro is defined to 1
and for every enabled to be built library a RTE_DEBUG_{library name}
and for every enabled to be built driver
a RTE_DEBUG_{driver_class}_{driver_name} is also defined.
These macros can be used to place a debug code
inside #ifdef #endif clauses.

The following requirements were discussed on the mailing list:
1) The global debug flag is required to enable all the sanity checks
and validations that are normally not used due to performance reasons

2) The best option would be to have a single flag - not to introduce
too many build options

3) This option should be separated from meson "debug" option
(used for build with symbols) and can be called "rte_debug"

4) The currently existing DEBUG macros should not be replaced with
a RTE_DEBUG macro. This would allow to still enable them using
CFLAGS="-D..." to test a single module (library, driver).

5) Currently existing options' names should be standardized
to RTE_DEBUG_{library/driver name}, so they can be automatically enabled
when rte_debug is set. Standardized names would allow easy usage
in other modules.

6) The debug functionality should be encapsulated in:
        if (rte_log_can_log(...)) {
                ...
        }
for possibility to be filtered out in runtime.


Because of the hot discussion of v1 version of patches, I limit
the v2 version to mbuf library changes only, to see how it will impact
the performance with rte_log_can_log usage and to get opinions.

v3 contains mbuf performance tests, which might help dpdk developers
community to decide if drop of performance related to rte_log_can_log
can be accepted.

If agreement is reached, next steps would be to follow changes
in other libraries and drivers.

---
v3:
* Define RTE_DEBUG_* flags also for drivers
* Bring back CONFIG option for librte_mbuf, but with new flag name
* Add mbuf performance tests

v2:
* Use new meson option rte_debug instead of debug
* Add standardized defines for built libraries
* Limit patches to mbuf library (as a POC)
* Use rte_log_can_log to wrap debug section

Lukasz Wojciechowski (4):
  config: introduce global rte debug flag
  config: remove unused config flags
  mbuf: standardize library debug flag
  app/test: add mbuf perf tests

 app/test/Makefile                  |   1 +
 app/test/meson.build               |   4 +-
 app/test/test_mbuf.c               |   3 +-
 app/test/test_mbuf_perf.c          | 273 +++++++++++++++++++++++++++++
 config/common_base                 |   6 +-
 config/meson.build                 |   4 +
 doc/guides/prog_guide/mbuf_lib.rst |   2 +-
 drivers/baseband/meson.build       |   1 +
 drivers/bus/meson.build            |   1 +
 drivers/common/meson.build         |   1 +
 drivers/compress/meson.build       |   1 +
 drivers/crypto/meson.build         |   1 +
 drivers/event/meson.build          |   1 +
 drivers/mempool/meson.build        |   1 +
 drivers/meson.build                |   3 +
 drivers/net/meson.build            |   1 +
 drivers/raw/meson.build            |   1 +
 drivers/vdpa/meson.build           |   1 +
 lib/librte_mbuf/rte_mbuf.h         |  12 +-
 lib/meson.build                    |   4 +
 meson_options.txt                  |   2 +
 21 files changed, 312 insertions(+), 12 deletions(-)
 create mode 100644 app/test/test_mbuf_perf.c

-- 
2.17.1