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Leopard Performance - Single or Multiple Dynamips Processes?

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Joined: 23 Mar 2007
Posts: 83

PostPosted: Thu Apr 17, 2008 9:20 pm    Post subject: Leopard Performance - Single or Multiple Dynamips Processes? Reply with quote

Has anybody done a performance comparison between running a single dynamips process vs many on a 64-bit OS with a large lab (20+ routers)?

I imagine that communications would be faster with a single process, but what about other aspects? My suspicion is that on my 8-core box I won't notice much of a difference.
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PostPosted: Fri Apr 18, 2008 2:33 pm    Post subject: Reply with quote

I've not tested it, but I'd bet you'd see zero difference. Whether the instances are running under one hypervisor or multiple ones on the same host, the communication is always via UDP NETIO bound to the loopback. So in theory there should be no difference at all.

Can you run 20 instances in a single process? I've not used dynamips with a 64 bit mac yet, but if it is anything like linux I would think there would need to be code changes to support 64 bit address space. I would suspect there would be the same 3 GB / process limitation even on a 64 bit machine.
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Joined: 19 Jan 2007
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PostPosted: Sun Apr 20, 2008 10:54 pm    Post subject: Reply with quote

I thought the 3 GB limitation is only on 32-bit linux? As far as I know, 32-bit linux uses a hack to get around the 2 GB limitation that 32-bit Windows is plagued with. 64 bit Linux and Leopard should have no problem with apps requiring more that 2 or 3 GB of memory. From what I read in this article http://arstechnica.com/reviews/os/mac-os-x-10-5.ars/6 the kernel in Leopard runs in 32 bit, but is quite happy to run apps in 64 bit mode.

But I will report back soon with facts when the 4 GB RAM upgrade for my MacBook arrives.

Mikej: Guessing you have an 8-core MacPro, let us know how Dynamips is doing on that machine!
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PostPosted: Mon Apr 21, 2008 1:17 am    Post subject: little update Reply with quote

I was able to fire up 16 x 3640's with 128 RAM each in one dynamips process, after that the Activity Monitor showed me that the dynamips process was using about 3.77 GB of Virtual RAM and didn't allow me to start any more routers in that process.


dynamips(139,0xb071b000) malloc: *** mmap(size=73195520) failed (error code=12)
*** error: can't allocate region
*** set a breakpoint in malloc_error_break to debug
load_elf_image: elf_begin: I/O error: file too big for memory
C3600 '30': failed to load Cisco IOS image '/Applications/Dynagen/images/c3640.bin'.

Guess around 4 GB for an application is the maximum under Leopard.

But that didn't stop me from starting another 16 routers in another process that consumed another 3.77 GB of virtual memory. (I have only 2 GB RAM installed) - Please note: None of the routers had any config on them and there was no topology involved!

=> list
Name Type State Server Console
10 3640 running localhost:7200 2020
11 3640 running localhost:7200 2021
12 3640 running localhost:7200 2022
13 3640 running localhost:7200 2023
14 3640 running localhost:7200 2024
15 3640 running localhost:7200 2025
16 3640 running localhost:7200 2026
17 3640 running localhost:7200 2027
18 3640 running localhost:7200 2028
19 3640 running localhost:7200 2029
20 3640 running localhost:7200 2030
21 3640 running localhost:7200 2031
22 3640 running localhost:7200 2032
23 3640 running localhost:7200 2033
24 3640 running localhost:7200 2034
25 3640 running localhost:7200 2035
26 3640 stopped localhost:7200 2036
27 3640 stopped localhost:7200 2037
28 3640 stopped localhost:7200 2038
29 3640 stopped localhost:7200 2039
40 3640 running localhost:7201 2040
30 3640 stopped localhost:7200 2040
41 3640 running localhost:7201 2041
42 3640 running localhost:7201 2042
43 3640 running localhost:7201 2043
44 3640 running localhost:7201 2044
45 3640 running localhost:7201 2045
46 3640 running localhost:7201 2046
47 3640 running localhost:7201 2047
48 3640 running localhost:7201 2048
49 3640 running localhost:7201 2049
50 3640 running localhost:7201 2050
51 3640 running localhost:7201 2051
52 3640 running localhost:7201 2052
53 3640 running localhost:7201 2053
54 3640 running localhost:7201 2054
55 3640 running localhost:7201 2055

...still not shabby at all I would say Very Happy

Some output from running top:

Processes: 157 total, 5 running, 2 stuck, 150 sleeping... 434 threads 01:47:17
Load Avg: 8.07, 10.40, 9.59 CPU usage: 75.65% user, 10.43% sys, 13.91% idle
SharedLibs: num = 8, resident = 32M code, 20K data, 2012K linkedit.
MemRegions: num = 9522, resident = 1568M + 9100K private, 142M shared.
PhysMem: 289M wired, 1163M active, 582M inactive, 2039M used, 9552K free.
VM: 15G + 373M 121148(0) pageins, 863510(396) pageouts

154 dynamips 79.1% 24:05.93 47 163 255 282M 544K 282M 3291M
139 dynamips 78.6% 18:18.31 59 191 316 1193M 544K 1194M 3420M
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PostPosted: Tue Apr 22, 2008 6:32 pm    Post subject: Reply with quote

from what I know is that every router is running under separate thread so in theory there should not be difference between one hypervisor and more hypervisors on same mashine.
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