Hi Thomas,
On 04/03/2017 09:57 PM, Thomas Petazzoni wrote:
>> So there's a small downside to this - which I reckon will likely not stand
>> out in
>> grand scheme of things - still tabling it here for people to be aware of.
>> This can potentially degrade some of the micro-benchmarks such as LMBench
>> lat_proc
>> shell - since there's now an additional shared library (libtirpc) to load. We
>> spotted this back in 2015 when comparing buildroot (using libtirpc) vs. our
>> homegrown builds (using native toolchain rpc).
> How big was the performance hit?
Processor, Processes - times in microseconds - smaller is better
------------------------------------------------------------------------------
Host OS Mhz null null open slct sig sig fork exec sh
call I/O stat clos TCP inst hndl proc proc proc
--------- ------------- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----
A7-720mhz Linux 3.4.61 720 0.50 0.97 4.37 9.38 26.0 1.00 5.59 1103 5061 8432
A7-720mhz Linux 3.4.61 720 0.50 0.96 4.24 9.31 26.0 1.00 5.59 1093 5029 10.K
So ~19%
> Is it just due to loading an
> additional library, or to internal RPC implementation aspects that
> differs between the uClibc built-in implementation and the libtirpc
> implementation?
So the thing is Busybox binary ends up being linked with 2 libs (instead of just
libc.so) thus ldso loading takes more time. Now lat_proc shell ends up doing
exec() of (busybox) shell and then hello world - hence the increased time.
> If it's just due to loading an additional library, is this micro
> benchmark really representative of real-world workload? Is it really a
> real life situation to have very short-lived processes that need RPC
> support?
Hard to judge really - for a desktop/server system it probably doesn't matter -
but for a typical embedded system ...
-Vineet
>
> Best regards,
>
> Thomas
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