Date: Sat, 17 May 2008 15:43:56 +0300 From: Evren Yurtesen <yurtesen@ispro.net> To: Evren Yurtesen <yurtesen@ispro.net>, Jeremy Chadwick <koitsu@FreeBSD.org>, freebsd-stable@freebsd.org Subject: Re: Approaching the limit on PV entries, consider increasing either the vm.pmap.shpgperproc or the vm.pmap.pv_entry_max sysctl. Message-ID: <482ED30C.3030802@ispro.net> In-Reply-To: <20080517005304.GA63122@voi.aagh.net> References: <482B4DEE.3050705@ispro.net> <20080515010347.GA85202@eos.sc1.parodius.com> <482BE398.8010203@ispro.net> <20080516182044.GA5921@voi.aagh.net> <482DD410.6090102@ispro.net> <20080517005304.GA63122@voi.aagh.net>
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Thomas Hurst wrote: > * Evren Yurtesen (yurtesen@ispro.net) wrote: > >> How do I see what process is sharing memory and how much memory? > > Guessing is normally sufficient; typically it's processes with the same > name and similar size/res. On 7-STABLE you can use procstat -v to look > at the VM mappings for a process, but typically that'll be overkill. Thanks, I will try to check procstat -v when I start seeing the error message coming. When the system is showing "Approaching the limit on PV entries" is it related to number of allocations I see in procstat -v output? Is each line an PV entry? How can one obtain same information from 6.x i386? (just asking to compare similar systems) >> There are a bunch of apache 2.2 processes working normally about 20-30 >> processes. This box doesnt do much more than that... >> >> I just checked the machine and here is what it looks like: >> 2:32PM up 18 days, 5:40, 3 users, load averages: 0.41, 0.36, 0.27 >> >> web:/root#ps ax |grep http >> 21429 ?? Ss 0:18.08 /usr/local/sbin/httpd >> 86473 ?? S 0:00.09 /usr/local/sbin/httpd >> 86659 ?? S 0:00.09 /usr/local/sbin/httpd >> >> Although I see now that for 2 days the PV entries error did not appear. I >> wonder if it is spooling up somehow... > > They do look a bit small to be triggering it; assuming they're sharing > most of that, that's still only about 400k pv entries; 5MB or so (12 > bytes per entry). The systems I've seen pv entries run out on run to a > couple of orders of magnitude more than that. >> There is a cron job restarting apache everyday at midnight so it cant >> be apache leaking perhaps. > > Load spikes maybe? Child count running into the stratosphere? Big PHP > opcode cache? The machine is primarily serving perl pages through mod_perl2 and there are a few PHP sites too but they are negligible. It is just that I never saw this kind of message coming out on 6.3-stable i386 with the same sites which is kind of weird. However a load spike might be the cause of course, I will try to catch this when PV entry warning appear. Now that I know that procstat can show me more info, I can try to collect some info to see if something looks weird. I will let you guys know of my findings. Thanks for the great help! This information was very useful. Thanks, Evren
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