[PATCH 0/3] SELinux scalability and analysis patches.

From: James Morris
Date: Mon Nov 15 2004 - 14:49:34 EST


The following patchset improves the scalability of SELinux by replacing
the global avc_lock with an RCU based scheme by Kaigai Kohei. The size of
the cache is made tunable, to allow administrators to tune systems for
different workloads, while statistics are exported via selinuxfs to allow
AVC performance to be monitored at a low level.

This code has been extensively tested and benchmarked (see benchmark
results below). Baseline performance is not improved, although it is
clear that dramatic scalability improvements are achieved.

Baseline performance and networking scalability are areas where work is
ongoing (in particular, we need to add caching of some network security
objects so that we don't fallback to policy database lookups on each
permission call).


- James
--
James Morris
<jmorris@xxxxxxxxxx>


Benchmark results:

===============================================================================================

System: 4 node 16-way IA64 NUMA

- 'Stream' is based on http://www.cs.virginia.edu/stream/ , HPC memory bandwidth test,
higher result is better.
- Hackbench: scheduler scalability benchmark by Rusty, lower is better.

Standard kernel:
2.6.9-1.648_EL SELINUX=0 : Stream 6159.987MB/s HackBench 53.144
2.6.9-1.648_EL SELINUX=1 : Stream 5872.529MB/s HackBench 1043.132

Kernel with RCU/AVC patches:
2.6.9-1.689_avcrcu.root SELINUX=0 : Stream 8829.647MB/s HackBench 53.976
2.6.9-1.689_avcrcu.root SELINUX=1 : Stream 8817.117MB/s HackBench 50.975

===============================================================================================

System: 8-way PIII 900Mhz Xeon with 9GB RAM
Fileystem: ext2 for all testing.

Notes:
AVC was reset before tests, so avc was flushed.
System was run in enforcing mode.

Key:
std-nolsm: standard kernel with LSM disabled
std-lsmcap: standard kernel with LSM enabled, capabilities LSM
std-sel-strict: standard kernel with SELinux enabled, capabilities secondary LSM
rcu-sel-strict: as above with RCU & AVC stats patches

---------------------------------------------------------------------------------------
Dbench
---------------------------------------------------------------------------------------
Notes:
100 iterations each, results are throughput in MB/sec (bigger is better)

----------------------------------------------------------------
# Clients 1 2 4 8
----------------------------------------------------------------
std-nolsm 151.1 270.3 460.4 699.0
std-lsmcap 152.6 273.3 465.4 703.5
std-sel-strict 142.4 254.5 428.1 598.5
rcu-sel-strict 143.3 261.0 437.1 680.7
----------------------------------------------------------------

---------------------------------------------------------------------------------------
Unixbench
---------------------------------------------------------------------------------------
Notes:
Run with parameters '-10 index'.
Overall score is an index, higher is better.


std-nolsm 328.0
std-lsmcap 327.9
std-sel-strict 311.1
rcu-sel-strict 305.9

---------------------------------------------------------------------------------------
Apachebench
---------------------------------------------------------------------------------------

Notes:
Loopback, httpd logging to /dev/null.
Client and server on same system (hence peaking before 8 clients).
Document size is 500kB, 20,000 requests.
Values are transfer rate in Kb/s received: bigger is better.

---------------------------------------------------------------------------------
Concurrency Level 1 2 4 8
---------------------------------------------------------------------------------
std-nolsm 43083.26 49740.85 48657.74 47913.67
std-lsmcap 43888.87 48943.08 49475.39 48657.81
std-sel-strict 33551.52 35082.17 34854.14 34363.09
rcu-sel-strict 33118.51 36509.20 36621.59 35903.92
---------------------------------------------------------------------------------

---------------------------------------------------------------------------------------
Webstone
---------------------------------------------------------------------------------------

Notes:
Two physical clients, each via private GigE links.
Result is total server throughput in Mb/s (bigger is better).
1 iteration for two minutes.

----------------------------------------------------------------
# Clients 2 4 8 16 32
----------------------------------------------------------------
std-nolsm 67.79 284.43 374.35 420.09 427.09
std-lsmcap 67.79 298.15 373.50 420.84 431.80
std-sel-strict 78.42 272.48 345.99 378.81 376.30
rcu-sel-strict 77.53 268.91 348.65 390.76 391.35
----------------------------------------------------------------

===============================================================================================

Testing by KaiGai on a 32-way system during development:
---------------------------------------------------------

The following three benchmark programs were used.
* parallel write() system call (my original)
- The results of 2.6.9.RCU scale linearly as 2.6.9(disable)
* dbench
- The results of 2.6.9.RCU are almost same as 2.6.9(disable).
The performance turned down in 32CPU, but I think it's a
problem with dbench. (I'm not so fine about dbench configuration :( )
* UNIX bench(micro benchmark)
- 2.6.9.RCU doesn't have a significant degration toward 2.6.9(enable)
These are as expected.

The raw results:
---- write() system call [Kcalls/sec] ---------------------
Num of CPUs -1CPU- -2CPU- -4CPU- -8CPU- -16CPU- -32CPU-
2.6.9(disable) 773.6 1611.4 3160.5 6301.0 12605.0 24296.4
2.6.9(enable) 535.8 655.8 241.8 127.7 62.9 30.2
2.6.9.RCU 542.5 1042.9 2301.6 4518.0 8963.5 18033.6
-----------------------------------------------------------

---- dbench Through-put [MB/sec] --------------------------
Num of CPUs -1CPU- -2CPU- -4CPU- -8CPU- -16CPU- -32CPU-
2.6.9(disable) 286.7 556.9 1056.0 1572.1 1663.1 395.5
2.6.9(enable) 268.7 500.5 771.4 381.3 164.3 84.2
2.6.9.RCU 270.0 524.2 994.8 1511.3 1489.5 386.9
-----------------------------------------------------------

---- UNIX bench Results [Index value] ---------------------
2.6.9(disable) 2.6.9(enable) 2.6.9.RCU
Dhrystone 2 275.8 275.8 275.8
D-P Whetstone 97.5 97.5 97.5
Execl Throughput 408.9 398.3 397.5
File Copy 1KB x 2000 blks 604.2 520.4 517.5
File Copy 256B x 500 blks 510.9 414.8 415.1
File Copy 4KB x 8000 blks 980.4 893.5 878.2
Pipe Throughput 510.4 403.5 396.9
Process Creation 253.5 251.2 249.7
Shell Scripts(8 concurrent) 1190.5 1165.0 1182.2
System Call Overhead 468.7 469.9 469.0
-----------------------------------------------------------
FINAL SCORE 434.6 403.6 402.2


===============================================================================================

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