Date: Mon, 8 Mar 2004 10:04:28 -0500 From: "Mike Jakubik" <mikej@rogers.com> To: "'Doug White'" <dwhite@gumbysoft.com> Cc: stable@freebsd.org Subject: RE: Semaphore scaling Message-ID: <20040308150343.DEFA434741.fep02-mail.bloor.is.net.cable.rogers.com@win2000> In-Reply-To: <20040304111724.K21028@carver.gumbysoft.com>
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> -----Original Message----- > From: Doug White [mailto:dwhite@gumbysoft.com] > Sent: Thursday, March 04, 2004 2:20 PM > To: mikej@rogers.com > Cc: stable@freebsd.org > Subject: Re: Semaphore scaling > > Don't crosspost lists. Thanks. > > On Thu, 4 Mar 2004 mikej@rogers.com wrote: > > > I am running an application (Plesk) on a 4.9 system that is > eating up > > all the semaphores and as a result some processes can't run. I have > > contacted the software company, and they asked me to increase the > > semaphore limits in the kernel. However their suggested settings > > seemed very unproportional to me. > > > > So my question is, how should I adjust the values, while keeping > > things in proportion? I wish to increase the default > semaphore limit > > of 10 to 20. Can I simply double the semaphore related values? > > The semaphore tunables aren't quite as obvious as they look. > There are limits on the size of various clusters of things > whos usage is heavily application-dependent. That being said, > FreeBSD traditionally has very low SYSVSHM/SEM/MSG limits, so > doubling them should be safe. I suggest using the ipcs(8) > command to monitor the usage and adjust accordingly. > > The Plesk-supplied limits seem OK to me too. I've put > Oracle-sized values in there and haven't had any bad effects .. yet :) > > Note that you can adjust these with loader tunables as well, > if you don't want to rebuild the kernel. They have the same > name as the sysctls that show the current values in kern.ipc. I have adjusted the variables in /etc/sysctl.conf as follows: kern.ipc.semmap=60 kern.ipc.semmni=20 kern.ipc.semmns=120 kern.ipc.semmnu=60 kern.ipc.semmsl=120 kern.ipc.semopm=200 kern.ipc.semume=20 However, when I do 'sysctl kern.ipc|grep sem' I get the floowing results: kern.ipc.semmap: 60 kern.ipc.semmni: 10 kern.ipc.semmns: 60 kern.ipc.semmnu: 30 kern.ipc.semmsl: 120 kern.ipc.semopm: 100 kern.ipc.semume: 10 kern.ipc.semusz: 92 kern.ipc.semvmx: 32767 kern.ipc.semaem: 16384 It seems that kern.ipc.semmni is not being incremented. Am I doing something wrong here? Is this variable not tunable at boot? Interesting enough, these values in LINT are represented as x+1, i.e. SEMMAP=31 and SEMMNI=11. Thanks.
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