Date: Sun, 10 Dec 2006 23:17:48 +0300 From: Ruslan Ermilov <ru@freebsd.org> To: Holtor <holtor@yahoo.com> Cc: stable@freebsd.org Subject: Re: kern.ipc.nsfbufs Max Value? Message-ID: <20061210201748.GB81270@rambler-co.ru> In-Reply-To: <718463.76303.qm@web31704.mail.mud.yahoo.com> References: <718463.76303.qm@web31704.mail.mud.yahoo.com>
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--7iMSBzlTiPOCCT2k Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Dec 10, 2006 at 08:23:00AM -0800, Holtor wrote: > I have an extremely busy web server here serving mostly static html pages > and images using apache 2.2.3 with sendfile enabled. It's a Dual Xeon > server with 4 GB RAM and I've tweaked many sysctl variables to help the > system chug along. At peak, apache is running nearly 1,500 child > processes. >=20 Have a look at ports/www/nginx for the alternative web server. > To my question, what is the max value of kern.ipc.nsfbufs and does it > depend on any other values? I had originally increased it to 32768 however > sfbufs got maxed out slowing the server. Then I increased it to 65536 and > currently have these results: >=20 > 45348/48844/65536 sfbufs in use (current/peak/max) >=20 > To me that's too close for comfort so I further tried to increase it to > 131072 however with that setting the system would not boot. The kernel > page faulted with an error in the swapper process until I decreased > kern.ipc.nsfbufs back to 65536. >=20 > Is there anyway to increase this value even higher? The server has nearly > 2.5 GB of free ram out of the 4 GB installed and the load averages are > very low 0.07, 0.15, 0.34 so hopefully it's possible to tweak this some > more. >=20 > Any ideas? >=20 On i386, the sfbufs are allocated from kernel_map which is basically limited by the amount of KVA. Try increasing KVA_PAGES to give more virtual space for the kernel (at the cost of reducing the virtual address space for userland); see the comments regarding this option in sys/i386/conf/NOTES. On amd64, you wouldn't have this problem as sf_bufs are only opaque objects there and don't consume real memory. Cheers, --=20 Ruslan Ermilov ru@FreeBSD.org FreeBSD committer --7iMSBzlTiPOCCT2k Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (FreeBSD) iD8DBQFFfGtsqRfpzJluFF4RAnT1AJ40clu2xYtR4StPgzhREAXlWMt63ACdH3yF d/Mds6G0Am8YsJMCuz7gCzE= =n1IV -----END PGP SIGNATURE----- --7iMSBzlTiPOCCT2k--
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