dovecot/auth CPU spikes

[nicolas at andrillon.net]

And output from strace, nothing i can make sense of really...

10:38:46.859514 epoll_wait(16, [{EPOLLIN, {u32=1696469520, u64=15038376972816}}], 17, -1) = 1
10:38:47.768364 accept(7, {sa_family=AF_LOCAL, NULL}, [2]) = 23
10:38:47.768687 getsockname(23, {sa_family=AF_LOCAL, sun_path="/var/run/dovecot/login/log255r"}, [31]) = 0
10:38:47.768945 fcntl(23, F_GETFL) = 0x2 (flags O_RDWR)
10:38:47.769132 fcntl(23, F_SETFL, O_RDWR|O_NONBLOCK) = 0
10:38:47.769316 write(5, "372f53453", 12) = 12
10:38:47.769529 read(4, "nBW211316333t371341203251206317b367220", 16) = 16
10:38:47.769747 fstat(23, {st_mode=S_IFSOCK|0777, st_size=0, ...}) = 0
10:38:47.769979 lseek(23, 0, SEEK_CUR) = -1 ESPIPE (Illegal seek)
10:38:47.770129 getsockname(23, {sa_family=AF_LOCAL, sun_path="/var/run/dovecot/login/log"e"}, [31]) = 0
10:38:47.770320 epoll_ctl(16, EPOLL_CTL_ADD, 23, {EPOLLIN|EPOLLPRI|EPOLLERR|EPOLLHUP, {u32=1696840896, u64=15038377344192}}) = 0
10:38:47.770533 write(23, "VERSIONt1t1nMECHtPLAINtplaintext"..., 118) = 118
10:38:47.770735 epoll_wait(16, [{EPOLLIN, {u32=1696840896, u64=15038377344192}}], 17, -1) = 1
10:38:47.770927 read(23, "VERSIONt1t1nCPIDt10995n", 8192) = 23
10:38:47.771109 epoll_wait(16, [{EPOLLIN, {u32=1696840896, u64=15038377344192}}], 17, -1) = 1
10:38:47.916004 read(23, "AUTHt1tPLAINtservice=imaptsecure"..., 8169) = 145
10:38:47.916428 writev(15, [{"PENALTY-GETt2001:41d0:a::", 25}, {"n", 1}], 2) = 26
10:38:47.916851 epoll_wait(16, [{EPOLLIN, {u32=1696458048, u64=15038376961344}}], 17, 5000) = 1
10:38:47.917177 read(15, "0 0n", 332) = 4
10:38:47.917478 writev(23, [{"CONTt1t", 7}, {"n", 1}], 2) = 8
10:38:47.917835 read(15, 0xdad65237f68, 328) = -1 EAGAIN (Resource temporarily unavailable)
10:38:47.918218 epoll_wait(16, [{EPOLLIN, {u32=1696840896, u64=15038377344192}}], 17, 149998) = 1
10:38:47.919198 read(23, "CONTt1tAG5pY29sYXNAYW5kcmlsbG9uL"..., 8024) = 52
10:38:49.558718 writev(23, [{"OKt1tuser=address at domain.nett", 32}, {"n", 1}], 2) = 33
10:38:49.558978 epoll_wait(16, [{EPOLLIN, {u32=1696470560, u64=15038376973856}}], 17, 150000) = 1