mjhjmtu

PHP 7.1.13 on CentOS 7.4.1708

Inexplicable lag (2 to 10 seconds) just invoking php, even with empty script or just to get version info. I have never seen this before on any system and I'm not sure how to debug or fix this.

The lag can range from 2 to 10 seconds. It should take mere milliseconds, as on other systems. No other programs are experiencing this lag.

system load is negligible:

08:32:00 up 8 days, 2:23, 1 user, load average: 0.26, 0.29, 0.35

Can anyone provide advice on this?

Benchmarks:

$ time php -v
PHP 7.1.13 (cli) (built: Jan 4 2018 15:22:08) ( NTS )
Copyright (c) 1997-2017 The PHP Group
Zend Engine v3.1.0, Copyright (c) 1998-2017 Zend Technologies
 with Zend OPcache v7.1.13, Copyright (c) 1999-2017, by Zend Technologies

real 0m1.916s
user 0m0.015s
sys 0m0.012s
$ time php -r ''

real 0m9.841s
user 0m0.015s
sys 0m0.009s

I'm not the admin of this machine, though I'm working with him to resolve this issue.

I can't say how this particular package was installed.

[edit]

it was recommended to run strace, and I noticed pauses at POLL. What is PHP poll doing?

poll([fd=3, events=POLLOUT], 1, 0) = 1 ([fd=3, revents=POLLOUT])

I'm trying to find out from the sys adm what is (or is supposed to be) on 10.226.139.110. It pings fine with no particular lag.

socket(AF_INET, SOCK_DGRAM|SOCK_NONBLOCK, IPPROTO_IP) = 3
connect(3, sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("10.226.139.110"), 16) = 0
poll([fd=3, events=POLLOUT], 1, 0) = 1 ([fd=3, revents=POLLOUT])
sendmmsg(3, MSG_CONFIRM, 50, msg_name(0)=NULL, msg_iov(1)=["!36711xxxyyy"..., 50], msg_controllen=0, msg_flags=MSG_CONFIRM, 50, 2, MSG_NOSIGNAL) = 2
poll([fd=3, events=POLLIN], 1, 5000) = 0 (Timeout)
socket(AF_INET, SOCK_DGRAM|SOCK_NONBLOCK, IPPROTO_IP) = 4
connect(4, sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("10.226.143.110"), 16) = 0
poll([fd=4, events=POLLOUT], 1, 0) = 1 ([fd=4, revents=POLLOUT])
sendmmsg(4, MSG_CONFIRM, 50, msg_name(0)=NULL, msg_iov(1)=["!36711xxxyyy"..., 50], msg_controllen=0, msg_flags=MSG_CONFIRM, 50, 2, MSG_NOSIGNAL) = 2
poll([fd=4, events=POLLIN], 1, 5000) = 1 ([fd=4, revents=POLLIN])
ioctl(4, FIONREAD, [148]) = 0
recvfrom(4, "!2420120011vcoloscrmweb16indepen"..., 2048, 0, sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("10.226.143.110"), [16]) = 148
poll([fd=4, events=POLLIN], 1, 2769) = 1 ([fd=4, revents=POLLIN])
ioctl(4, FIONREAD, [148]) = 0
recvfrom(4, "!36720120011xxxyyy"..., 65536, 0, sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("10.226.143.110"), [16]) = 148
close(3) = 0
close(4) = 0
socket(AF_INET, SOCK_DGRAM|SOCK_NONBLOCK, IPPROTO_IP) = 3
connect(3, sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("10.226.139.110"), 16) = 0
poll([fd=3, events=POLLOUT], 1, 0) = 1 ([fd=3, revents=POLLOUT])

--

php -m

[PHP Modules]
apcu
bcmath
bz2
calendar
Core
ctype
curl
date
dom
exif
fileinfo
filter
ftp
gd
gettext
hash
iconv
igbinary
imap
json
libxml
mbstring
mcrypt
memcached
mysqli
mysqlnd
openssl
pcntl
pcre
PDO
pdo_mysql
pdo_sqlite
Phar
posix
readline
Reflection
session
shmop
SimpleXML
sockets
SPL
sqlite3
sqlsrv
standard
sysvmsg
sysvsem
sysvshm
tokenizer
wddx
xml
xmlreader
xmlwriter
xsl
Zend OPcache
zip
zlib

[Zend Modules]
Zend OPcache

Issue was that the value of /etc/hostname was not mapped in /etc/hosts to a local IP address. AND the IMAP module (imap.so) tries to resolve the hostname at init time (for reasons I can not comprehend), querying DNS. The hostname for this particular host was not registered in the company's DNS.

solution: edit /etc/hosts

127.0.0.1 [whatever the /etc/hostname is] 

(or some other local IP address)

thanks for your help @ramansailopal

https://serverfault.com/questions/586141/php-cli-with-imap-5-second-startup-delay