We've been noticing a significant slowdown of one of our applications when migrated to Ubuntu Hardy, amd64. It runs perfectly well on Debian Sarge i386.
Running an 'strace -r' against the (Apache 1.3) httpd process has shown the following troubling section:
0.000083 poll([{fd=8, events=POLLIN|POLLERR, revents=POLLIN}], 1, -1) = 1
0.000026 recvfrom(8, "_323-412D\0\0\0000\0\2\0\0\0\17recueil-cours"..., 32727, 0, NULL, NULL) = 8192
0.000061 poll([{fd=8, events=POLLIN|POLLERR, revents=POLLIN}], 1, -1) = 1
0.000026 recvfrom(8, "\0\0\0000\0\2\0\0\0\17recueil-courses\0\0\0\23er2"..., 32767, 0, NULL, NULL) = 2369
0.117422 brk(0x397a000) = 0x397a000
0.140721 brk(0x399b000) = 0x399b000
4.457037 brk(0x39bc000) = 0x39bc000
0.078792 stat("/opt/semantico/slot/nijhoff/3/sitecode/live/public_home.html", {st_mode=S_IFREG|0644, st_size=2194, ...}) = 0
Note the brk on the last-but-one line - implying that the brk(0x399b000) took 4.45 seconds!
I've checked out the man page for brk, which points at it being used for requesting a larger data segment/heap, but I can't find any reason why it would take so long.
Anyone got any ideas?