Question about srcbody in VCL_conf

Gordon Schmidt at
Mon Jul 2 13:10:09 CEST 2012

Dear Varnish-Team,

while trying to optimize varnish performance for my company i've 
noticed, that removing all comments from the vcls used in our 
configuration tribles the requests per seconds from an easy ab test with 
100% cache-misses. On an ab test with 100% cache-hits the improvement 
was about 8-10%. I was a little bit shocked, because i've read that the 
vcls are compiled to c and execution shouldn't depend on the amount of 

I took a deeper look and found out, that the compiler appends a char 
array of the vcl source (srcbody) to the VCL_conf. Which operations need 
this data?

If these operations are not crucial for an production environment (e.g. 
if it's just used for tracing and source output with -C), could you 
please add an option to prevent the compiler to add such additional 
information to the VCL_conf?
These operations would have to be reviewed, so they still work with this 
option activated (if with less verbosity because of the missing data).
I know it's very helpful to have such informations in an staging 
environment, but i wouldn't use tracing in production and so i might not 
need this extra data there. The performance gain on the other hand could 
be noticeable.

I might get a performance boost with the recent version of varnish 
already by just minifying the vcl's in the deployment, but there still 
would be a lot of data left in the VCL_conf, that may not be needed imo.

I hope you can shed some light on this matter.



*Gordon Schmidt*
Softwareentwickler - QA

Unister GmbH
Barfußgässchen 11 | 04109 Leipzig

Telefon: +49 (0)341 65050 - 25757 at < at> <>

Vertretungsberechtigter Geschäftsführer: Thomas Wagner
Amtsgericht Leipzig, HRB: 19056

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