[squid-users] Squid performance not able to drive a 1Gbps internet link

[Amos Jeffries]

On 4/08/2016 2:32 a.m., Heiler Bemerguy wrote:
> 
> I think it doesn't really matter how much squid sets its default buffer.
> The linux kernel will upscale to the maximum set by the third option.
> (and the TCP Window Size will follow that)
> 
> net.ipv4.tcp_wmem = 1024 32768 8388608
> net.ipv4.tcp_rmem = 1024 32768 8388608
> 

Having large system buffers like that just leads to buffer bloat
problems. Squid is still the bottleneck if it is sending only 4KB each
I/O cycle to the client - no matter how much is already received by
Squid, or stuck in kernel queues waiting to arrive to Squid. The more
heavily loaded the proxy is the longer each I/O cycle gets as all
clients get one slice of the cycle to do whatever processing they need done.

The buffers limited by HTTP_REQBUF_SZ are not dynamic so its not just a
minimum. Nathan found a 300% speed increase from a 3x buffer size
increase. Which is barely noticable (but still present) on small
responses, but very noticable with large transactions.

Amos