82xx performance

[Rune Torgersen]

Hi

We are looking into switching kernels from 2.6.18 (ppc) to 2.6.25
(powerpc).
I have been trying to run some benchmarks to see how the new kernel
compares to the old one.

So far it is performing worse.

One test I ran was just compiling a 2.6.18 kernel on the system.
The .25 performed 5 to 7 % slower:

2.6.18, make vmlinux
real    74m1.328s
user    68m48.196s
sys     4m35.961s

2.6.25, make vmlinux
real    79m13.361s
user    72m41.318s
sys     5m46.744s

I also ran lmbench3. (slightly outdated, but still works)
Most (if not all) results are worse on .25, especially context
switching.

Is this expected behaviour or is there anything I need to look at in my
config?
(I'll send config if anybody is interested)


                 L M B E N C H  3 . 0   S U M M A R Y
                 ------------------------------------
                 (Alpha software, do not distribute)

Basic system parameters
------------------------------------------------------------------------
------
Host                 OS Description              Mhz  tlb  cache  mem
scal
                                                     pages line   par
load
                                                           bytes
--------- ------------- ----------------------- ---- ----- ----- ------
----
9919_unit  Linux 2.6.25       powerpc-linux-gnu  434    32    32 1.0000
1
9919_unit  Linux 2.6.18       powerpc-linux-gnu  445    32    32 1.0100
1

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
--------- ------------- ---- ---- ---- ---- ---- ---- ---- ---- ----
---- ----
9919_unit  Linux 2.6.25  434 0.47 1.26 10.7 35.6 34.1 1.76 14.3 2646
9964 33.K
9919_unit  Linux 2.6.18  445 0.35 1.24 9.27 22.9 32.7 1.87 13.8 2157
7825 26.K

Basic integer operations - times in nanoseconds - smaller is better
-------------------------------------------------------------------
Host                 OS  intgr intgr  intgr  intgr  intgr
                          bit   add    mul    div    mod
--------- ------------- ------ ------ ------ ------ ------
9919_unit  Linux 2.6.25 2.3300 0.0100   10.7   46.2   56.0
9919_unit  Linux 2.6.18 2.2300 0.0100   10.3   45.4   54.1

Basic float operations - times in nanoseconds - smaller is better
-----------------------------------------------------------------
Host                 OS  float  float  float  float
                         add    mul    div    bogo
--------- ------------- ------ ------ ------ ------
9919_unit  Linux 2.6.25 9.9500   10.1   46.2   66.2
9919_unit  Linux 2.6.18 9.1100 9.0800   45.8   67.1

Basic double operations - times in nanoseconds - smaller is better
------------------------------------------------------------------
Host                 OS  double double double double
                         add    mul    div    bogo
--------- ------------- ------  ------ ------ ------
9919_unit  Linux 2.6.25 9.3400   11.6   78.6  100.2
9919_unit  Linux 2.6.18 9.1600   11.1   77.2   97.8

Context switching - times in microseconds - smaller is better
------------------------------------------------------------------------
-
Host                 OS  2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K
16p/64K
                         ctxsw  ctxsw  ctxsw ctxsw  ctxsw   ctxsw
ctxsw
--------- ------------- ------ ------ ------ ------ ------ -------
-------
9919_unit  Linux 2.6.25   20.6   86.2   28.5  103.8   38.7   111.8
57.4
9919_unit  Linux 2.6.18 5.3300   63.2   17.9   73.4   23.1    74.9
26.2

*Local* Communication latencies in microseconds - smaller is better
---------------------------------------------------------------------
Host                 OS 2p/0K  Pipe AF     UDP  RPC/   TCP  RPC/ TCP
                        ctxsw       UNIX         UDP         TCP conn
--------- ------------- ----- ----- ---- ----- ----- ----- ----- ----
9919_unit  Linux 2.6.25  20.6  68.8 131. 353.1 533.4 461.7       1269
9919_unit  Linux 2.6.18 5.330  36.1 87.8 225.3 402.7 331.8 520.1 970.

File & VM system latencies in microseconds - smaller is better
------------------------------------------------------------------------
-------
Host                 OS   0K File      10K File     Mmap    Prot   Page
100fd
                        Create Delete Create Delete Latency Fault  Fault
selct
--------- ------------- ------ ------ ------ ------ ------- -----
------- -----
9919_unit  Linux 2.6.25  222.3  172.4 1003.0  350.5   41.5K 1.734
10.5  18.0
9919_unit  Linux 2.6.18  181.5  144.3  789.3  293.9   23.9K
7.09560  19.3

*Local* Communication bandwidths in MB/s - bigger is better
------------------------------------------------------------------------
-----
Host                OS  Pipe AF    TCP  File   Mmap  Bcopy  Bcopy  Mem
Mem
                             UNIX      reread reread (libc) (hand) read
write
--------- ------------- ---- ---- ---- ------ ------ ------ ------ ----
-----
9919_unit  Linux 2.6.25 34.2 34.7 21.5   55.5  161.8   79.9   79.2 160.
116.1
9919_unit  Linux 2.6.18 40.1 37.4 29.7   60.0  165.8   80.6   81.1 165.
117.8

Memory latencies in nanoseconds - smaller is better
    (WARNING - may not be correct, check graphs)
------------------------------------------------------------------------
------
Host                 OS   Mhz   L1 $   L2 $    Main mem    Rand mem
Guesses
--------- -------------   ---   ----   ----    --------    --------
-------
9919_unit  Linux 2.6.25   434 4.8150  174.6  183.3       511.8    No L2
cache?
9919_unit  Linux 2.6.18   445 4.6880  174.1  175.4       497.5    No L2
cache?