[sugar] secure /tmp and /var/tmp

NoiseEHC NoiseEHC at freemail.hu
Thu Nov 8 06:14:10 EST 2007


>> 2) How much can the flash drive handle per throughput AND lifetime limits?
>>   
>>     
>
> Throughput is dominated by compression / decompression.  The latter goes 
> at about 3 MB/sec; the former is probably slower.
>   
Assuming that 50% of time is spent in decompression:
433.000.000/3.000.000/2 = 72 clocks per byte

Has anybody profiled JFFS2?

Looking at zlib_inflate_fast() in inffast.c it seems that all it does is 
grabbing some bits from the input and copies bytes to the output. With 
my physic debugging skills I can only conclude that the time is spent on 
mispredicted branches (5-8 clocks each) and cache misses (25? each). 
Probably it would worth rewriting inffast.c in asm (162 lines) once the 
profiler points to that as a bottleneck.

Is read speed a bottleneck during boot or app loading?



More information about the Devel mailing list