On Thu, 2006-04-27 at 13:37 -0700, Wes Shull wrote: > On 4/27/06, Andrew Haley <aph@xxxxxxxxxx> wrote: > > It works for me, bouncing data back and forth. What does it do on > > your box? What is the output? > > unadultered output at http://kuoi.asui.uidaho.edu/~wes/out.txt ; here > is an abbreviated annotated version: > > Creating listener on 3000 > Connecting to listener on 127.0.0.1:3000 > [...] > Creating listener on 3499 > Connecting to listener on 127.0.0.1:3499 > > I'm doing the connect asynchronously so all this really says it that > it's not hitting the file descriptor limit... > > client: 3499<-marco > server: 3499 accepted > [...] > client: 3482<-marco > server: 3482 accepted > > 18 of the connections are made and the server side sees the data, but... > > client: 3481<-marco > [...] > client: 3000<-marco > > The other 500-18 connections are never accepted. Tcl channels also go > writable on error (and I just realized my code doesn't check for that) > so it's probable it shouldn't even have been trying to send on these > because they never connected. > > client_readable: 3000 went away > [...] > client_readable: 3481 went away > > Here the client side catches that the other 500-18 connections didn't make it > > server: 3482<-marco > [...] > server: 3499<-marco > > server: 3499->polo > [...] > server: 3482->polo > > client: 3482->polo > [...] > client: 3499->polo > > client: 3499<-marco > [...] > client: 3482<-marco > > These last four sequences continue ad infinitum; it's successfully > passing data back and forth, but only on those 18 connections. > > Just for S&G, I ran this on a FreeBSD 6.0-RELEASE-p4 system, and while > it doesn't behave exactly the same, it didn't do what I expected there > either. Just to make sure I'm not running into some issue with > different Tcl builds (limited event queue length, limited # of active > connections), I'll rewrite this in C (bleah) tonight and see if it > behaves any better. Seems it is the kernel refusing to accept() any more connections, the reason being that it takes 2 descriptors for each of your listeners:- $ strace -e trace=socket,accept,connect ./sock.tcl Creating listener on 3000 socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 5 Connecting to listener on 127.0.0.1:3000 socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 6 connect(6, {sa_family=AF_INET, sin_port=htons(3000), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 EINPROGRESS (Operation now in progress) Creating listener on 3001 socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 7 Connecting to listener on 127.0.0.1:3001 socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 8 connect(8, {sa_family=AF_INET, sin_port=htons(3001), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 EINPROGRESS (Operation now in progress) ... So when you come to connect you only get: ulimit(1024) - 2*500 - initialFD(5) = 19 for new connections:- server: 3484 accepted client: 3483<-marco accept(971, {sa_family=AF_INET, sin_port=htons(44952), sin_addr=inet_addr("127.0.0.1")}, [8589934608]) = 1021 server: 3483 accepted client: 3482<-marco accept(969, {sa_family=AF_INET, sin_port=htons(56034), sin_addr=inet_addr("127.0.0.1")}, [8589934608]) = 1022 server: 3482 accepted client: 3481<-marco accept(967, {sa_family=AF_INET, sin_port=htons(38003), sin_addr=inet_addr("127.0.0.1")}, [8589934608]) = 1023 server: 3481 accepted client: 3480<-marco accept(965, 0x7fffffa7d020, [8589934608]) = -1 EMFILE (Too many open files) client: 3479<-marco accept(963, 0x7fffffa7d020, [8589934608]) = -1 EMFILE (Too many open files) client: 3478<-marco accept(961, 0x7fffffa7d020, [8589934608]) = -1 EMFILE (Too many open files) client: 3477<-marco accept(959, 0x7fffffa7d020, [8589934608]) = -1 EMFILE (Too many open files) client: 3476<-marco ... If run as root with and raise the limit to 10k then you see 1500 file descriptors once the test is fully connected. Perhaps the most confusing thing is that the second FD for each listener doesn't appear in /proc/<pid>/fd until something connects. Notice how you only see odd numbered FD's for the unconnected listeners below. $ ls -l /proc/29381/fd | sort -n -k 9 0 -> /dev/pts/0 1 -> /home/jburgess/socket/out 2 -> /home/jburgess/socket/out 3 -> pipe:[8919517] 4 -> pipe:[8919517] 5 -> socket:[8919518] 7 -> socket:[8919520] 9 -> socket:[8919522] 11 -> socket:[8919524] 13 -> socket:[8919526] Jon -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
