[Dnsmasq-discuss] [PATCH] Optimize speed on massive server=/.../... records

[Simon Kelley]

Thanks for this. It was in my mind that vary large number of domains 
would be --local=/domain/ or --address=/domain/, not forwarding to servers.

I've applied something that looks very like your patch, but with 
cosmetic code changes.

Cheers,

Simon.


On 20/11/2022 05:50, Ye Zhou wrote:
> Hi all,
> 
> I'm attaching a patch to optimize a speed issue introduced in version 2.86.
> 
> I have two ISP upstreams and need to forward different sites to 
> different ISP's DNS providers. For example:
> 
> server=/meituan.com/114.114.114.114 <http://meituan.com/114.114.114.114>
> ... (lots of records)
> server=/taobao.com/223.5.5.5 <http://taobao.com/223.5.5.5>
> ... (lots of records)
> 
> It works well before v2.86. Since v2.86 the configuration load time 
> becomes extremely long (more than 1 minutes to load all server records). 
> The time consuming part is inside the rewritten domain-match.c. When 
> adding a new server record, the code will traverse all existing records 
> so the configuration load becomes quadratic time complexity. The issue 
> still persists on v2.88rc3.
> This patch will optimize the config load time by bypassing the time 
> consuming code block. During the config load mark_servers() will never 
> be called so does not need to waste time on the record traversal and 
> re-order part.
> 
> Before:
> dnsmasq --test  77.50s user 0.30s system 99% cpu 1:17.84 total
> After:
> dnsmasq --test  0.16s user 0.02s system 99% cpu 0.188 total
> 
> https://gist.github.com/zhouye/adfd509f51645d314f53992331449c45 
> <https://gist.github.com/zhouye/adfd509f51645d314f53992331449c45>
> 
> 
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