On 2014-09-10 16:28, Peter Meerwald wrote:
> Hello David,
>
>>> The remapper and channel mixing code have (faster) specialized and (slower)
>>> generic code certain code path. The flag force_generic_code can be set to
>>> force the generic code path which is useful for testing. Code duplication
>>> (such as in mix-special-test) can be avoided, cleanup patches follow.
>>>
>>> Signed-off-by: Peter Meerwald <pmeerw at pmeerw.net>
>>> ---
>>> src/Makefile.am | 2 +-
>>> src/daemon/main.c | 4 +++-
>>> src/pulsecore/cpu.c | 28 ++++++++++++++++++++++++++++
>>> src/pulsecore/cpu.h | 5 +++++
>>> src/pulsecore/mix.c | 8 ++++++++
>>> src/pulsecore/remap.c | 13 +++++++++++++
>>> 6 files changed, 58 insertions(+), 2 deletions(-)
>>> create mode 100644 src/pulsecore/cpu.c
>>>
>>> diff --git a/src/Makefile.am b/src/Makefile.am
>>> index 51ef690..634e26b 100644
>>> --- a/src/Makefile.am
>>> +++ b/src/Makefile.am
>>> @@ -897,7 +897,7 @@ libpulsecore_ at PA_MAJORMINOR@_la_SOURCES = \
>>> pulsecore/rtpoll.c pulsecore/rtpoll.h \
>>> pulsecore/stream-util.c pulsecore/stream-util.h \
>>> pulsecore/mix.c pulsecore/mix.h \
>>> - pulsecore/cpu.h \
>>> + pulsecore/cpu.c pulsecore/cpu.h \
>>> pulsecore/cpu-arm.c pulsecore/cpu-arm.h \
>>> pulsecore/cpu-x86.c pulsecore/cpu-x86.h \
>>> pulsecore/cpu-orc.c pulsecore/cpu-orc.h \
>>> diff --git a/src/daemon/main.c b/src/daemon/main.c
>>> index 02a8ea6..74527be 100644
>>> --- a/src/daemon/main.c
>>> +++ b/src/daemon/main.c
>>> @@ -1050,13 +1050,15 @@ int main(int argc, char *argv[]) {
>>> #endif
>>>
>>> c->cpu_info.cpu_type = PA_CPU_UNDEFINED;
>>> + c->cpu_info.force_generic_code = false; /* use generic, slow code */
>>
>> Are you sure this comment is correct? It looks like the opposite.
>
> the comment is not very clear at least; it describes the purpose of the
> flag, not the assignment
>
> replacing it with
> /* don't force generic code, used for testing only */
> in v2
>
>> Also, what is the difference between setting force_generic_code and setting
>> PULSE_NO_SIMD?
>
> mixing and remapping as generic and special-case code; the flag can be
> set to force use of the generic code
> this is useful for the test code so that special-case code can be compared
> with the (presumably correct) generic code -- it saves quite a lot of code
> in the test suits (the alternative would be to expose the internal
> mixing/remapping function); special-case code path are beneficial on all
> CPUs
>
> PULSE_NO_SIMD suppresses CPU-specific code path
I first confused "special-case code" with "CPU-specific code", but is
this correct:
"special-case code" is when you e g have a special function for "mono to
stereo" conversion instead of the generic "m to n channels" conversion,
whereas "CPU-specific code" means code that uses special instructions
(usually hand written assembly)
And then there is orc, which seems to count as "CPU-specific code" in
this context.
I guess the "force_generic_code" name was too generic for me to
understand :-) maybe two bitflags would be even better, e g
"use_cpu_specific_code" and "use_special_case_code", or something...
--
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic
