Hi Bogdan You don't have to give up device polling because of SMP. I run several fbsd 4.9-stable (dual PIII) with device polling. Go to /sur/src/sys/kern/kern_poll.c , outcomment the SMP part, add device polling, hz= et al to kernel, recompile, set sysctl variables, reboot and you're done. Works like a charm.
respectfully /per [EMAIL PROTECTED] > > Hi Peter and all, > > Thanks for the mails & advices... The box is a dual xeon @3GHz, > with 4GB of ram and raid 5 on board (scsi HDDs), with a 4.9 on it. > The 'tuning' includes removing all the unnecessary stuff from the > kernel, activating the ACCEPT_FILTERS and tuning some sysctl > values, > especially the ones dealing with network (net.inet.tcp.msl etc.), > and raising the values for maxfiles and somaxconn, etc. The box has > two NICs, one of them is a fxp with link0 activated (cannot use > polling because I don't want to give up SMP -- the userland > activity is > already 40%, so giving up one CPU as to reduce sys load it's just > gonna leave the bottleneck where it is -- CPU, that is), and the > other one is an em, but cannot use it since i don't have a gb > switch. Before activating link0 on fxp, the level of interrups/sec > on this interface peaked 6k, but after activating link0 it was > reduced to 2k. Still, a lot of sys activity... > > As a webserver, I run apache, stripped down from the modules that I > don't need, and compiled in php and some other modules > (statically). Most of the content that I serve is static, there are > only a few php scripts and they don't get much hits. > > I don't run any other 'intensive computing' application on the > server, no firewall software or so. And no, I haven't tried turning > HTT on and off, should I do that? > > I am also considering trussing one of the apaches, to see what > system calls it's doing... > > Anyways, thanks for your help, > bogdan > > > On Tue, Mar 16, 2004 at 06:06:01PM +1100, Peter Jeremy wrote: >> On Mon, Mar 15, 2004 at 04:04:38PM +0100, Bogdan TARU wrote: >> > I'm running a pretty busy webserver, and right now I can see >> > it's CPU-bound: >> >> A few more details would be useful: >> What version of FreeBSD? >> What hardware are you using (CPU and NIC in particular)? >> What application(s) are you running? You mention a webserver - >> which one? >> Is it just serving static pages or is there lots of dynamic >> content (CGI or servlet etc)? Any other applications? >> Do you have firewall software running? If so, which? Is it >> simple (a dozen >> or so rules) or complex (thousands of rules)? >> What FreeBSD tuning have you done? >> How does your kernel config compare to GENERIC? > >> If the CPU supports HTT, have you tried turning HTT on and off? >> >> >84 2 0 1135836 142692 82 0 0 0 405 0 35 0 3144 >> >246325 1739 42 58 0 >> >> You have very high interrupt and system call rate - both of these >> contribute to system time. >> >> I presume most of the interrupts are from your NIC. Have you >> considered using polling mode (see polling(4))? Some NICs are >> more efficient than others - fxp(4) is one of the best, rl(4) is >> probably the worst. >> >> It's difficult to say whether the syscall rate is excessive or >> not. The number of system calls is generally up to the application >> - you need to tune or redesign it to reduce the number of system >> calls it makes per unit of work. That said, I've noticed that >> threading on -STABLE adds quite a significant overhead - via high >> system call rate and system time. In one case, I improved the >> throughput of a graphics manipulation process by about 10% by >> removing the threading. >> >> It's difficult to get much visibility on where system time is >> going (though "systat -v" will split out interrupt time). In >> theory, you could build a profiling kernel but this is non-trivial >> and may or may not be functional at present. >> >> Peter >> _______________________________________________ >> [EMAIL PROTECTED] mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers >> To unsubscribe, send any mail to >> "[EMAIL PROTECTED]" > _______________________________________________ > [EMAIL PROTECTED] mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to > "[EMAIL PROTECTED]" _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
