On 22 November 2011 19:29, Mark Saad <nones...@longcount.org> wrote: > Hello All
[found this mail in my drafts, not sure if my answer is still useful] > I want to get to the bottom of a warning in dmesg. On 7.2-RELEASE and > 7.3-RELEASE I have seen the following warning in dmesg. > > Approaching the limit on PV entries, consider increasing either the > vm.pmap.shpgperproc or the vm.pmap.pv_entry_max sysctl. > > So looking around I see a few posts here and there about how to tune > the sysctls to address the warning however I am not 100% sure what > each value does. > It appears changing vm.pmap.shpgperproc affects the value of > vm.pmap.pv_entry_max . Can someone explain the relationship of the two > sysctls. Also This is how they are calculated. pv_entry_max = shpgperproc * maxproc + cnt.v_page_count; and, respectively, shpgperproc = (pv_entry_max - cnt.v_page_count) / maxproc; So, changing one sysctl will change another and vice versa. > what pitfalls of changing them are. Not known to me (on amd64 platform). I have had vm.pmap.shpgperproc=15000 on 8.1 amd64 with 4G RAM to make some badly written commercial software to work until it was decommissioned to the scrap. > Also why would setting > kern.ipc.shm_use_phys=1 effect the pv entries. Is this supposed to > lower the pv entries ? Changing this sysctl with restarting a quite busy PgSQL server helped me to reduce pv entries from 14M to tens of thousands (though that could just coincide with decrease in workload). -- wbr, pluknet _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
