mbox series

[API-NEXT,v3,00/11] Use HW time counter

Message ID 20170428120958.17526-1-petri.savolainen@linaro.org
Headers show
Series Use HW time counter | expand

Message

Petri Savolainen April 28, 2017, 12:09 p.m. UTC 
This patch set modifies time implementation to use TSC when running on a x86 
CPU that has invarint TSC CPU flag set. Otherwise, the same Linux system time 
is used as before. TSC is much more efficient both in performance and 
latency/jitter wise than Linux system call. This can be seen also with 
scheduler latency test which time stamps events with this API. All latency 
measurements (min, ave, max) improved significantly.

This is sent through api-next as cpu flags are printed through new system info 
print function for debugging purposes (to verify that invariant TSC flag is 
read correctly).

Patch 3/8 causes two checkpatch errors due to code copied from DPDK. Both 
the macro and the ifdef cannot be changed, so errors should be ignored.

v2:
  * Use ODP_PRINT instead of printf
  * Removed couple of time.hw.reserved set to zero. One remains since otherwise
    GCC suspects usage of unintialized variable (false warning).
  * Fixed install of new arch/x86/cpu_flag files

v3:
  * patch 1/11:  Remove odp_time_to_u64() as unnecessary, nsec time is u64
  * patch 10/11: Slightly improved TSC frequency measument accuracy due to
                 fewer but longer sample runs
  * patch 11/11: Lower odp_time_t memory footprint due to converting timespec 
                 to nsec time before storing into odp_time_t

Petri Savolainen (11):
  api: time: remove odp_time_to_u64 from API
  api: system: added system info print
  linux-gen: cpu_flags: added x86 cpu flag read functions
  linux-gen: system: implement system info print
  test: validation: add odp_sys_info_print test
  test: sched_latency: use sys_info_print
  test: validation: rename time test header file
  test: validation: add time accuracy test
  linux-gen: time: use hw time counter when available
  linux-gen: time: improve x86 TSC freq measurement accuracy
  linux-gen: time: store timespec as nsec

 configure.ac                                       |   1 +
 include/odp/api/spec/system_info.h                 |   9 +
 include/odp/api/spec/time.h                        |  13 -
 platform/Makefile.inc                              |   4 +-
 platform/linux-generic/Makefile.am                 |   5 +
 platform/linux-generic/arch/arm/odp_cpu_arch.c     |  16 +
 .../linux-generic/arch/arm/odp_sysinfo_parse.c     |   4 +
 platform/linux-generic/arch/default/odp_cpu_arch.c |  16 +
 .../linux-generic/arch/default/odp_sysinfo_parse.c |   4 +
 platform/linux-generic/arch/mips64/odp_cpu_arch.c  |  16 +
 .../linux-generic/arch/mips64/odp_sysinfo_parse.c  |   4 +
 platform/linux-generic/arch/powerpc/odp_cpu_arch.c |  16 +
 .../linux-generic/arch/powerpc/odp_sysinfo_parse.c |   4 +
 platform/linux-generic/arch/x86/cpu_flags.c        | 368 +++++++++++++++++++++
 platform/linux-generic/arch/x86/cpu_flags.h        |  20 ++
 platform/linux-generic/arch/x86/odp_cpu_arch.c     |  68 ++++
 .../linux-generic/arch/x86/odp_sysinfo_parse.c     |   6 +
 .../include/odp/api/plat/time_types.h              |  19 +-
 platform/linux-generic/include/odp_internal.h      |   1 +
 platform/linux-generic/include/odp_time_internal.h |  24 ++
 platform/linux-generic/odp_system_info.c           |  30 ++
 platform/linux-generic/odp_time.c                  | 256 +++++++++-----
 test/common_plat/performance/odp_sched_latency.c   |  18 +-
 test/common_plat/validation/api/system/system.c    |   8 +
 test/common_plat/validation/api/system/system.h    |   1 +
 test/common_plat/validation/api/time/Makefile.am   |   2 +-
 test/common_plat/validation/api/time/time.c        |  77 +++--
 test/common_plat/validation/api/time/time_main.c   |   2 +-
 .../validation/api/time/{time.h => time_test.h}    |   2 -
 29 files changed, 863 insertions(+), 151 deletions(-)
 create mode 100644 platform/linux-generic/arch/x86/cpu_flags.c
 create mode 100644 platform/linux-generic/arch/x86/cpu_flags.h
 create mode 100644 platform/linux-generic/include/odp_time_internal.h
 rename test/common_plat/validation/api/time/{time.h => time_test.h} (92%)

-- 
2.11.0