Hey everyone --
First of all, I apologize if this is an inappropriate forum for this...
but perhaps someone has an idea...
So, we installed a new cluster here with some Athlon 64 machines... and
we're finding that these new machines are quite a bit slower than our old
AMD64 test machine...
So I ran lmbench 3.0 on these machines to see if I could find some of the
bottlenecks -- and came up with the following:
Two machines were tested -- CT4 and CT115:
CT4 is an opteron 1.8 with a 9.3 normal install. CT115 is an Athlon 64
3400+ (clock at 2400 Ghz) with a diskless install (and we've tried the
same hardware with a normal non-diskless install and the results are
simular...)
So some of the basic results were what we'd expect... numbers were better
on CT115:
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
--------- ------------- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----
----
ct4 Linux 2.6.4-5 1786 0.10 0.39 4.46 5.09 15.2 0.31 1.22 115. 480.
2886
ct115 Linux 2.6.16. 2410 0.07 0.13 1.42 2.17 9.29 0.19 1.07 113. 393.
4223
Float/Int, etc.. numbers blew the CT4 machine too...
But then we get to some of the context switching tests for example:
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
--------- ------------- ------ ------ ------ ------ ------ ------- -------
ct4 Linux 2.6.4-5 0.5200 0.6600 5.2300 2.3500 5.7400 2.48000 18.0
ct115 Linux 2.6.16. 0.5400 0.5800 3.1800 1.8900 26.0 3.83000 49.5
After we get to 8p/64K and above, the numbers are quite bad as you can
see...
And the Bcopy and memory numbers:
*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
--------- ------------- ---- ---- ---- ------ ------ ------ ------ ----
-----
ct4 Linux 2.6.4-5 1077 1149 520. 1136.2 2453.4 938.2 938.6 2427
1360.
ct115 Linux 2.6.16. 1798 2062 269. 259.3K 1489.2 391.6 389.4 1483
578.8
So, where should I be looking here in order to get these machines up to
where they should be? Anyone have any ideas to help me overcome this
issue? Is it hardware or software? Would a memory issue cause this?
Even though they both have 1Gb PC3200 memory, CT4 has ECC memory and CT116
just has regular el-cheapo Corsair memory. Would that make a difference
here?
Thanks!
Shaun
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