Date: Thu, 23 Aug 2012 01:00:19 GMT From: Navdeep Parhar <np@FreeBSD.org> To: freebsd-net@FreeBSD.org Subject: Re: kern/170713: [cxgb] Driver must be loaded after boot due to timing issues checking for kern.ipc.nmb* values set via /boot/loader.conf Message-ID: <201208230100.q7N10J9C000372@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
The following reply was made to PR kern/170713; it has been noted by GNATS. From: Navdeep Parhar <np@FreeBSD.org> To: bug-followup@FreeBSD.org, yanegomi@gmail.com Cc: Subject: Re: kern/170713: [cxgb] Driver must be loaded after boot due to timing issues checking for kern.ipc.nmb* values set via /boot/loader.conf Date: Wed, 22 Aug 2012 17:56:34 -0700 First, note that only kern.ipc.nmbclusters is a valid tunable. The rest of the nmbXXX settings in your loader.conf have no effect. There are sysctls but no tunables for the rest. Take a look at tunable_mbinit in kern_mbuf.c -- on recent FreeBSD versions it starts with nmbclusters and sizes others based on this. You can set nmbclusters really high and influence the values of the other parameters. In my opinion we should have a TUNABLE_INT_FETCH for all of the nmbXXX and autocalculate the ones that are not set, just like what we do for nmbclusters today. static void tunable_mbinit(void *dummy) { TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters); /* This has to be done before VM init. */ if (nmbclusters == 0) nmbclusters = 1024 + maxusers * 64; nmbjumbop = nmbclusters / 2; nmbjumbo9 = nmbjumbop / 2; nmbjumbo16 = nmbjumbo9 / 2; } Compare this to the tunable_mbinit in 7 and you can see why the nmbclusters tunable does not affect the others -- it is updated after the other values have already been calculated. static void tunable_mbinit(void *dummy) { /* This has to be done before VM init. */ nmbclusters = 1024 + maxusers * 64; nmbjumbop = nmbclusters / 2; nmbjumbo9 = nmbjumbop / 2; nmbjumbo16 = nmbjumbo9 / 2; TUNABLE_INT_FETCH("kern.ipc.nmbclusters", &nmbclusters); } Regards, Navdeep
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201208230100.q7N10J9C000372>