Would anyone be able to shed some light on some intruging performance data for
the Gigabit Ethernet perfomance on the Z ? Any assistance would be greatly
appreciated.
The config:
This is a z800 with a Gigabit Ethernet card. There are about 4 unused instances
on the IFL. The Linux instances use C-T-C for the interfaces. The OS is a fully
updated RHEL v 3.0 64 bit. 256 MB RAM.
# ps ax | awk '$5 =="[nfsd]" {print $5}' | wc -l
32
# sysctl -a | egrep "net.core.[r,w]mem_*"
net.core.rmem_default = 262144
net.core.wmem_default = 262144
net.core.rmem_max = 262144
net.core.wmem_max = 262144
# cat /proc/net/rpc/nfsd
rc 10085 980625 19695632
fh 30 20677891 0 41743 348
io 192032246 2587893200
th 32 52458 5602.460 353.890 317.360 70.470 224.040 199.110 191.900 183.960
0.000 568.060
ra 64 23319 494 254 637 107 124 120 162 85 44 3321
net 20687188 20373787 313401 10
rpc 20686342 846 0 846 0
proc2 18 4 16171822 3717 0 165036 235 26159 0 268736 4393 18452 805 430 116 136
828 4554 13376
proc3 22 8 3234603 1026 28629 19049 67 2510 683335 1180 4 7 848 1728 2 245 168
1688 194 6442 5682 0 18927
> In this test I would expect the maximum possible performace. What we have is
> stlpr001 as an NFS server, serving out my ID's home directory to stlpr004.
> i.e. stlpr004:/u/$ID
>
> I then take the special UNIX device called /dev/zero and build a 16 Kilobyte
> block of data, 16384 times, creating a 256 Megabyte flatfile called
> zerofile_Z, into the NFS mounted directory. This should be extremely fast,
> since it should not go out to the rest of the network and compete for
> bandwidth. I would exepect to see a minimum of around 300 Mbit per second.
> Instead, we get a dissmal 11 Mbit per second.
>
> stlpr004:/u/$ID $> time dd if=/dev/zero of=~/zerofile_Z bs=16k count=16384
> 16384+0 records in
> 16384+0 records out
>
> real 3m4.996s
> user 0m0.030s
> sys 0m54.700s
>
> stlpr004:/u/$ID $> ls -l zerofile_Z
> -rw-rw-r-- 1 ze92387 ze92387 268435456 Jan 9 14:29 zerofile_Z
>
> stlpr004:/u/$ID $> bc
> bc 1.06
> Copyright 1991-1994, 1997, 1998, 2000 Free Software Foundation, Inc.
> This is free software with ABSOLUTELY NO WARRANTY.
> For details type `warranty'.
>
> 268435456 * 8 .... to a convert Bytes to bits
> 2147483648
> 2147483648 / 184 ..divided by the number of seconds to get throughtput.
> 11671106 ... 11.67 Mbits per second
>
> Roughly 11 Mbits per second. Really, pretty bad.
>
>
> Cheers;
>
> E!
>
> -----------------
> Eric Wilson
>
>
