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Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!elroy.jpl.nasa.gov!usc!wupost!gumby!yale!zip.eecs.umich.edu!congo.eecs.umich.edu!khushro From: khushro@congo.eecs.umich.edu (Khushro Shahookar) Newsgroups: comp.os.386bsd.questions Subject: Swapping Question Date: 29 May 1993 19:47:47 GMT Organization: University of Michigan Engineering, Ann Arbor Lines: 103 Distribution: world Message-ID: <1u8el3$7uk@zip.eecs.umich.edu> Reply-To: khushro@congo.eecs.umich.edu (Khushro Shahookar) NNTP-Posting-Host: congo.eecs.umich.edu The following memory statistics show that although 16MB RAM is installed in my system, only 5MB is actually being used, and the rest of the 8MB of processes are swapped out. The last ps at the end shows that all of the RAM did indeed get used, but only when the virtual memory size grew beyond 32 Meg. In other words, more than half of the virtual memory is always swapped out, regardless of whether the RAM is filled up or not. Questions: 1. If we have sufficient RAM, isn't everything supposed to run completely in RAM? 2. Why should any page get swapped out when the RAM is still empty, even if the page has not been used for a long time? 3. Is this a bug or a feature of NetBSD? 4. Did I do anything wrong here? 5. Why does swapinfo -k show half the virtual memory usage compared to ps? The Netbsd ps(1) says that ps reports in Kbytes by default, just like swapinfo -k. vmstat procs memory page disks faults cpu r b w avm fre flt re pi po fr sr ?0 ?1 ?2 ?3 in sy cs us sy id 0 0 0 4600 8488 5 0 1 1 0 0 0 0 0 0 116 43 13 3 3 94 danube# ps -augx USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND root 160 2.3 6.7 2112 1016 ?? S 1:36PM 0:53.80 X :0 root 230 0.0 0.5 176 64 p2 I+ 2:42PM 0:00.40 rlogin congo.ee root 229 0.0 0.8 176 120 p2 Is+ 2:42PM 0:00.99 rlogin congo.ee root 228 0.0 5.4 1000 828 vg I 2:42PM 0:02.31 xterm -tn xterm root 180 0.0 0.4 116 56 ?? Is 1:36PM 0:00.10 /usr/gnu/epoch/ root 175 0.0 1.3 268 184 p1 Is+ 1:36PM 0:01.18 -sh (csh) root 174 0.0 1.1 248 164 p0 Ss 1:36PM 0:00.47 -sh (csh) root 232 0.0 1.1 256 168 p0 R+ 3:01PM 0:00.06 ps -augx root 172 0.0 0.2 1064 20 vg I 1:36PM 0:00.53 /usr/bin/X11/xv root 171 0.0 1.3 648 188 vg I 1:36PM 0:00.48 xclock -digital root 170 0.0 2.0 1040 304 vg I 1:36PM 0:01.78 xman -bothshown root 169 0.1 2.7 916 400 vg S 1:36PM 0:01.65 /usr/bin/X11/xt root 168 0.0 4.0 1496 608 vg I 1:36PM 0:04.30 /usr/gnu/bin/em root 167 0.0 2.9 916 444 vg S 1:36PM 0:03.72 /usr/bin/X11/xt root 173 0.0 2.6 752 384 vg S 1:36PM 0:03.11 twm root 161 0.0 0.2 160 20 vg I 1:36PM 0:00.21 sh /root/.xinit root 159 0.0 0.2 216 20 vg I+ 1:36PM 0:00.13 xinit root 153 0.0 0.5 248 76 vg Is 1:35PM 0:00.33 -csh (csh) root 87 0.0 0.2 168 20 ?? Is 1:33PM 0:00.13 inetd nobody 80 0.0 0.2 176 20 ?? Is 1:33PM 0:00.03 rwalld root 61 0.0 0.2 152 20 ?? Is 1:33PM 0:00.03 portmap root 59 0.0 0.2 176 20 ?? Is 1:33PM 0:00.79 lpd root 53 0.0 0.6 188 84 ?? I 1:33PM 0:00.12 /usr/libexec/cr root 51 0.0 0.3 72 32 ?? Is 1:33PM 0:00.32 update root 39 0.0 0.5 148 72 ?? Is 4:36PM 0:00.19 timed root 36 0.0 0.7 156 96 ?? Ss 4:36PM 0:00.26 syslogd root 2 0.0 0.1 0 12 ?? DL 4:36PM 0:08.12 (swapper) root 1 0.0 0.3 140 44 ?? Is 4:36PM 0:00.12 init - root 0 0.0 0.1 0 0 ?? DLs 4:36PM 0:00.02 (scheduler) TOTAL 13184 5484 danube# swapinfo -k Device Kilobytes Used Available Capacity /dev/sd0b 76800 7761 69038 10% /dev/wd0b 0 *** not available for swapping *** ------- When all the RAM is used ------ ps -augx USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND root 209 5.7 72.0 26276 11040 p1 S 2:28PM 1:05.88 emacs -nm root 2 5.1 0.1 0 12 ?? RL 4:36PM 0:05.28 (swapper) root 216 2.0 1.1 256 168 p1 R+ 2:32PM 0:00.09 ps -augx root 160 1.9 5.1 2112 772 ?? S 1:36PM 0:32.15 X :0 root 175 0.0 1.2 264 172 p1 Ss 1:36PM 0:00.94 -sh (csh) root 174 0.0 0.5 248 76 p0 Is+ 1:36PM 0:00.39 -sh (csh) root 173 0.0 1.5 752 216 vg S 1:36PM 0:02.28 twm root 172 0.0 0.2 1064 20 vg I 1:36PM 0:00.53 /usr/bin/X11/xv root 171 0.0 0.9 648 136 vg I 1:36PM 0:00.47 xclock -digital root 170 0.0 0.2 1040 20 vg I 1:36PM 0:01.64 xman -bothshown root 169 0.0 0.2 916 28 vg I 1:36PM 0:01.31 /usr/bin/X11/xt root 168 0.0 3.3 1496 500 vg I 1:36PM 0:03.94 /usr/gnu/bin/em root 167 0.4 2.3 916 340 vg S 1:36PM 0:03.00 /usr/bin/X11/xt root 161 0.0 0.2 160 20 vg I 1:36PM 0:00.21 sh /root/.xinit root 180 0.0 0.3 116 36 ?? Is 1:36PM 0:00.07 /usr/gnu/epoch/ root 159 0.0 0.2 216 20 vg I+ 1:36PM 0:00.13 xinit root 153 0.0 0.5 248 76 vg Is 1:35PM 0:00.33 -csh (csh) root 87 0.0 0.2 168 20 ?? Is 1:33PM 0:00.13 inetd nobody 80 0.0 0.2 176 20 ?? Is 1:33PM 0:00.03 rwalld root 61 0.0 0.2 152 20 ?? Is 1:33PM 0:00.03 portmap root 59 0.0 0.2 176 20 ?? Is 1:33PM 0:00.79 lpd root 53 0.0 0.6 188 84 ?? I 1:33PM 0:00.11 /usr/libexec/cr root 51 0.0 0.3 72 32 ?? Ss 1:33PM 0:00.27 update root 39 0.0 0.3 148 44 ?? Is 4:36PM 0:00.16 timed root 36 0.0 0.4 156 52 ?? Ss 4:36PM 0:00.21 syslogd root 210 0.0 0.2 116 20 ?? Is 2:28PM 0:00.04 /usr/gnu/epoch/ root 1 0.0 0.3 140 44 ?? Is 4:36PM 0:00.11 init - root 0 0.0 0.1 0 0 ?? DLs 4:36PM 0:00.02 (scheduler) TOTAL 38220 14008 -Khushro