Date: Fri, 14 Mar 2003 15:54:13 -0800 From: "Andrew Kinney" <andykinney@advantagecom.net> To: freebsd-hackers@freebsd.org Subject: increasing KVA_PAGES and broken pthreads Message-ID: <3E71FB25.27881.363E6F4@localhost>
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Hello, I'm brand new to this list so feel free to tell me to search the archives if this question has already been answered. I have already done some searching and only found limited and/or antiquated information on the subject, though, so I'm pretty sure this hasn't been addressed yet. Does anyone know if a PR was ever submitted for the issue at: http://www.mail-archive.com/freebsd-hackers@freebsd.org/msg38532.html I know from reading the thread that a patch was created and sent to this list. Was that patch ever made a part of the CVS tree? If so, what branch would I have to track to pick up that patch? I'd like to avoid adding patches that CVSup will clobber later. I've seen this same issue with FreeBSD 4.5-RELEASE running on a heavily loaded web/mail/database server with dual CPU and 4GB of RAM and 8GB of available swap (no swapping activity). Setting KVA_PAGES=512 rather than the default 256 caused MySQL to die repeatedly with signal 6 as fast as it could respawn itself. The MySQL daemon was compiled on another FreeBSD 4.x system and was part of a prepackaged application from a commercial vendor. I've already tuned the system quite a bit to get around a lot of the "large memory" issues. However, because of all the tuning to avoid running out of various kernel resources before we ran out of physical RAM, we're now running out of KVM or will very soon. %sysctl -a |grep kvm vm.kvm_size: 1065353216 vm.kvm_free: 4194304 %sysctl kern.maxusers kern.maxusers: 384 (the autoscale max) In particular, we had to take PMAP_SHPGPERPROC up to 1500 from the default of 200 due to the large amount of shared memory pages that Apache needs to do its job efficiently. That puts KVM usage by PV Entries alone to nearly 300MB. We were getting kernel panics every time we ran out of available PV Entries (vm.zone: PV ENTRY), so this was very necessary. We also had to increase NMBCLUSTERS to 12800 (higher than the autoscale max). This also put some pressure on free KVM. We're now tracking RELENG_4_7 (FreeBSD 4.7-RELEASE + security fixes). I haven't tried changing KVA_PAGES since version 4.5 and I'm a little gun-shy on changing that particular tunable since it has so many potential application gotchas, like with pthreads. The RELENG_4_7 CVS tree (updated yesterday) doesn't appear to have the patch mentioned in the thread I referenced in the URL at the beginning of my message. Our version string for that file: * $FreeBSD: src/lib/libc_r/uthread/uthread_init.c,v 1.23.2.7 2001/11/03 00:33:07 peter Exp $ IMHO, this issue could be a royal pain in the butt when I start working on quad processor systems with 32GB of RAM (not unrealistic at this company). I'd like to stay with FreeBSD, but the issues with large memory support are rapidly becoming more prominent due to the *huge* memory systems in use here, with even larger memory systems on the way in the near future. I came from the Linux camp (back when 2.0/2.2 kernels were the newest in use) and I don't want to have to go back, though I no longer have any clue how those boys handle large memory systems. Maybe they're not any better in that department. I just happen to like FreeBSD better and would prefer to stick with it if possible. So, to recap my questions, what branch would I have to track to pick up that patch to pthreads? If there is no branch with that patch, has a PR been submitted so it can eventually be included in the source? If so, what is the PR number? If not, what's the best way to submit a PR? Thanks in advance for any assistance in this matter. Sincerely, Andrew Kinney President and Chief Technology Officer Advantagecom Networks, Inc. http://www.advantagecom.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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