Website loading speed and peak response time?

Question

Client side optimization

Good day to all!

Please help me figure it out:
There is a site on VDS: 600 MHz 256 mb of FreeBSD memory, a bunch of Nginx + php-fpm + eAccelerator + MySQL
Based on data from Loadstorm.com stress tests (a pretty good speed tester, but the free version has a limit of 25 users ) and loadimpact.com (the limit is already 50 users, but you can't run it more than 4 times in 24 hours), the average site load time is 0.9 seconds. (~ 1.5 sec at 100 active users in loadimpact.com report here )

But very often the site load time "momentarily" increases (by about 1 in 20 requests, the load time is not ~0.9 sec as usual, but 6-7 seconds, sometimes even 15-20 seconds). It can be seen in the pictureresponse time, peak .



The load on the VDS is normal, ~ 5% percent, ~ 40% memory. There are no denials.



What could be the problem? In which direction to dig?

Answer 1

Understood more or less. There were two problems:
1) php-fpm rights. Each pool needs to be assigned a user from which it will work exactly the same under which the rights of the site user.
2) php-fpm settings max_children increased from standard 5 to 150 in Nginx worker_processes 2 worker_connections 5000. This is on VDS 256 Mb of memory. Takes 130 - 160 mb.

Answer 2

See if you have the same problem .

Answer 3

check I/O
gstat, top (memory), atop (memory,disks)

Answer 4

Maybe it's running out of processes that php-fpm creates and it's waiting for someone to release the process? At least the phrase about 1 to 20 hints at dependence on some kind of constant.