[squid-dev] [PATCH] Increase request buffer size to 64kb

[Alex Rousskov]

On 03/29/2016 06:06 PM, Nathan Hoad wrote:

> This (very small) patch increases the request buffer size to 64kb, from 4kb.

> -#define HTTP_REQBUF_SZ  4096
> +#define HTTP_REQBUF_SZ  65535


> In my testing, this increases throughput rather dramatically for
> downloading large files:

Based on your results alone, it is clear that the patch does more than
"increases the request buffer size"(*). IMO, the important initial
questions we need to answer are:

  1. Why the performance is improved in this micro test?
  2. What are the expected effects on other traffic?

Increasing a buffer sizes will naturally improve performance on a
micro-test that targets that buffer(*), but we should know more before
deciding whether this increase is _generally_ useful and whether there
is a better way to achieve similar (or better) performance results.


Please note that this message is not meant to disparage your email or
even the proposed change itself! I am just trying to explain what
additional information is needed in order to start making an _informed_
decision about the proposed change. Needless to say, many changes have
been committed without proper disclosures and analysis, but we should
strive to do better.


Thank you,

Alex.
P.S. (*) The changed constant _name_ has nothing to do with the micro
test: download vs. "request buffer size". IIRC, the constant itself is
misnamed/misused, but that tidbit may be just the tip of the iceberg.