Re: Apache + mod_php performance

On 9/28/2024 8:50 PM, Arne Vajhøj wrote:

With KeepAlive On then we have a performance problem.
 The cause is that worker processes are unavailable while
waiting for next request from client even though client is
long gone.
 That indicates that the cap is:
 max throughput (req/sec) = MaxClients / KeepAliveTimeout
 The formula holds for low resulting throughput but it does
not scale and seems to be more like 1/3 of that for higher
resulting throughput.
 But if one wants keep alive enabled, then it is something one
can work with.
 My experiments indicate that:
 KeepAlive On
KeepAliveTimeout 15 -> 1
MaxSpareServers 50 -> 300
MaxClients 150 -> 300
 is almost acceptable.
 nop.txt : 100 req/sec

MaxSpareServers increase is necessary to improve numbers. It seems
like without that then Apache spend too much time killings childs
when not needed and starting them when needed (and process creation
is expensive on VMS).
Downside is obviously that all those processes are kept even
if load is small for a long time.
Arne