Nmap Development mailing list archives
Re: nmap 5 memory usage
From: David Fifield <david () bamsoftware com>
Date: Mon, 23 Nov 2009 14:27:14 -0700
On Fri, Nov 20, 2009 at 05:29:26PM -0700, David Fifield wrote:
On Sun, Nov 08, 2009 at 12:15:39PM +0200, Dimitrios Apostolou wrote:Hello nmap hackers, I just run latest nmap on an old PC with 128MB RAM and a few other programs running. The system slowed down significantly and started swapping like crazy. I'm just reporting it here because it seems that system requirements have been significantly raised without anyone noticing (if this is intentional please just ignore me). By pmap'ing the process I got about 70MB of anonymous memory mappings. My command line was as simple as 'nmap -A $IPADDR'. What do you think?I tried this command with the Massif memory profiler. For me it grows to about 70 MB too. It turns out that almost all of this (over 80%) is from parsing the nmap-os-db file. http://www.bamsoftware.com/wiki/Nmap/Memory#a20091120 The OS database has been growing, but the bigger cause is probably the increase in the size of each test value, which was increased from 128 to 256 in r11074 in November 2008. All test values are allocated the same amount of memory, which is very wasteful because most values a shorter than 10 bytes. This is another target of the memory use reduction campaign.
I've been working on making OS scan more efficient in terms of memory, and I just merged my changes. There's a record of progress starting at http://www.bamsoftware.com/wiki/Nmap/Memory#a20091120 I ran Massif before and after with the command "nmap -O", then added up the parts that belong to OS scan. Before this merge the memory usage was 66,832,396 bytes, and after it was 2,815,061, a decrease of about 95%. The biggest gain came from storing unique strings only once. David Fifield _______________________________________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/mailman/listinfo/nmap-dev Archived at http://seclists.org/nmap-dev/
Current thread:
- nmap 5 memory usage Dimitrios Apostolou (Nov 09)
- Re: nmap 5 memory usage David Fifield (Nov 20)
- Re: nmap 5 memory usage David Fifield (Nov 23)
- Re: nmap 5 memory usage Fyodor (Nov 23)
- Re: nmap 5 memory usage David Fifield (Nov 23)
- Re: nmap 5 memory usage David Fifield (Nov 20)