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 (slightly outdated, but still works)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?
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