Re: RCU issue with SELinux (Re: SELINUX performance issues)

[James Morris]

On Tue, 24 Aug 2004, Kaigai Kohei wrote:

> o UNIXbench
> 
> * INDEX value comparison
>                                        2.6.8.1   2.6.8.1   2.6.8.1   2.6.8.1
>                                      (Disable)  (Enable)  (rwlock)     (RCU)
> Dhrystone 2 using register variables    268.9     268.8     269.2     269.0
> Double-Precision Whetstone               94.2      94.2      94.2      94.2
> Execl Throughput                        388.3     379.0     377.8     377.9 +
> File Copy 1024 bufsize 2000 maxblocks   606.6     526.6     515.6     504.8 *
> File Copy 256 bufsize 500 maxblocks     508.9     417.0     410.4     395.2 *
> File Copy 4096 bufsize 8000 maxblocks   987.1     890.4     876.0     857.9 *
> Pipe Throughput                         525.1     406.4     404.5     408.8 +
> Process Creation                        321.2     317.8     315.9     316.3 +
> Shell Scripts (8 concurrent)           1312.8    1276.2    1278.8    1282.8 +
> System Call Overhead                    467.1     468.7     464.1     467.2 +
>                                     ========================================
>      FINAL SCORE                        445.8     413.2     410.1     407.7

This benchmark somewhat characterizes 1P performance, and the ones I've 
marked with (*) get noticably worse with the RCU patch compared to the 
current locking scheme.  Tests marked (+) show no or insignificant 
improvement.

Might be useful to compare with the lmbench macrobenchmark, to see if it 
shows a similar pattern.

> o dbench [ 4 processes run parallely on 4-CPUs / 10 times trials ]
>                   ---- mean ----  - STD -
> 2.6.8.1(disable)  860.249 [MB/s]   44.683
> 2.6.8.1(enable)   714.254 [MB/s]   32.359
> 2.6.8.1(+rwlock)  767.904 [MB/s]   27.968
> 2.6.8.1(+RCU)     830.678 [MB/s]   16.352

Can you show the figures for 1 and 2 clients?

> In IA-32 or x86_64, can anybady implement atomic_inc_return()?
> If it can not, I'll try to make alternative macros or inline functions.

If you can get this done, it will be very useful, as I could allso run 
some benchmarks on my test systems.


- James
-- 
James Morris
<jmorris@xxxxxxxxxx>





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