Date: Fri, 30 May 1997 20:22:51 -0700 (PDT) From: Julian Elischer <julian@FreeBSD.ORG> To: hackers@FreeBSD.ORG Subject: Thundering herd. Message-ID: <199705310322.UAA17301@freefall.freebsd.org>
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hmm with processes doing a select on a socket..
here's an example from a ktrace'd kernel.
327 httpd 865038867.185613 CSW resume kernel
327 httpd 865038867.185955 CSW stop kernel
320 httpd 865038867.186244 CSW resume kernel
320 httpd 865038867.187107 CSW stop kernel
183 xlated 865038867.187475 CSW resume kernel
183 xlated 865038867.187767 CSW stop kernel
213 inetd 865038867.188044 CSW resume kernel
213 inetd 865038867.188335 CSW stop kernel
169 routed 865038867.188645 CSW resume kernel
169 routed 865038867.188961 CSW stop kernel
200 dhcpd 865038867.189294 CSW resume kernel
200 dhcpd 865038867.189626 CSW stop kernel
800 telnetd 865038867.189910 CSW resume kernel
800 telnetd 865038867.190232 CSW stop kernel
10166 httpd 865038867.190535 CSW resume kernel
10166 httpd 865038867.190853 RET select 1
10166 httpd 865038867.191171 CALL sigaction(0x1e,0xefbfdd44,0xefbfdd38)
10166 httpd 865038867.191468 RET sigaction 0
10166 httpd 865038867.191732 CALL accept(0x6,0xefbfdd74,0xefbfdd70)
10166 httpd 865038867.192080 RET accept 7
10166 httpd 865038867.192366 CALL sigaction(0x1e,0xefbfdd44,0xefbfdd38)
10166 httpd 865038867.192645 RET sigaction 0
10166 httpd 865038867.192926 CALL getsockname(0x7,0xefbfdd84,0xefbfdd70)
10166 httpd 865038867.193246 RET getsockname 0
10166 httpd 865038867.193518 CALL setsockopt(0x7,0x6,0x1,0xefbfdd50,0x4)
10352 httpd 865038867.194071 CSW resume kernel
10352 httpd 865038867.194387 CSW stop kernel
8735 telnetd 865038867.194681 CSW resume kernel
8735 telnetd 865038867.195075 CSW stop kernel
206 inetd 865038867.195393 CSW resume kernel
206 inetd 865038867.195701 CSW stop kernel
363 atalkd 865038867.195992 CSW resume kernel
363 atalkd 865038867.196330 CSW stop kernel
194 named 865038867.196634 CSW resume kernel
194 named 865038867.196954 CSW stop kernel
334 xntpd 865038867.197250 CSW resume kernel
334 xntpd 865038867.197556 CSW stop kernel
108 syslogd 865038867.197843 CSW resume kernel
108 syslogd 865038867.198150 CSW stop kernel
10077 httpd 865038867.198477 CSW resume kernel
10077 httpd 865038867.198778 CSW stop kernel
38 restartd 865038867.199095 CSW resume kernel
38 restartd 865038867.199394 CSW stop kernel
433 telnetd 865038867.199693 CSW resume kernel
433 telnetd 865038867.200010 CSW stop kernel
370 nmbd 865038867.200320 CSW resume kernel
370 nmbd 865038867.200623 CSW stop kernel
137 mpd 865038867.200933 CSW resume kernel
137 mpd 865038867.201318 CSW stop kernel
78 paneld 865038867.201646 CSW resume kernel
78 paneld 865038867.201970 CSW stop kernel
10166 httpd 865038867.202289 RET setsockopt 0
one 'wakeup' and a whole bunch of processes were woken up..
can't we do better than that?
this is in 2.2+
julian
p.s. yes it only wasted 10mSec (probably less without ktrace)
but I thought we had got around this..
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