On Tue, Jul 17, 2012 at 8:10 PM, Michael Rash <[email protected]> wrote: > On Sun, Jul 15, 2012 at 7:17 PM, C Anthony Risinger <[email protected]> wrote: >> >> ... this server is almost 100% idle right now (in fact, Linode panel >> shows less than 1MiB *total* traffic in 5 days ... couple ssh sessions >> only). fwknopd uses a consistent 0.3-0.9% CPU at all times, >> interrupting frequently. same results on ARMv7 pandaboard. strace >> shows rapid nanosleep() + poll() loop: >> >> [...] >> nanosleep({0, 10000000}, NULL) = 0 >> poll([{fd=4, events=POLLIN}], 1, 0) = 0 (Timeout) >> nanosleep({0, 10000000}, NULL) = 0 >> poll([{fd=4, events=POLLIN}], 1, 0) = 0 (Timeout) >> nanosleep({0, 10000000}, NULL) = 0 >> poll([{fd=4, events=POLLIN}], 1, 0) = 0 (Timeout) >> [...] >> >> ... how can this be remedied? bleh, i also had a related questions >> but it's escaping me for now ... >> > > In the fwknop-2.0 release there are two configuration variables in the > /etc/fwknop/fwknopd.conf file that control how long fwknopd sleeps in the > packet acquisition loop (PCAP_LOOP_SLEEP) and how many packets are processed > for each loop iteration (PCAP_DISPATCH_COUNT). By default, PCAP_LOOP_SLEEP > is set to 10,000 microseconds, or 1/10th of a second, and the > PCAP_DISPATCH_COUNT is set to zero meaning all packets seen in the interval > (some older versions of libpcap don't accept zero here and would expect some > other positive integer). > > I'd say that the PCAP_LOOP_SLEEP variable should be increased on your > system. On my system, I can get fwknopd to consume a lot of CPU if I reduce > PCAP_LOOP_SLEEP. Perhaps the default should be, say, closer to 1/3rd of a > second or something though.
i think we might have the decimal in the wrong place here :-) i microsecond == 1 millionth of a second ... default 10,000 microsecond PCAP_LOOP_SLEEP therefore equates to a 100hz loop, not 10hz. empirical evidence seem to support this: # sudo timeout 10s strace -p `pgrep fwknop` |& grep Timeout | wc -l 948 ... so i'm simply strace'ing and counting the number of timeouts. in 10 seconds i'm seeing almost 1000 timeouts, ie. ~100 timeouts-per-second. i bumped this to a full second at it seems to work just a s well. thanks Michael! -- C Anthony ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Fwknop-discuss mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/fwknop-discuss
