curl-library
Aw: Re: DNS Lookup time (CURLINFO_NAMELOOKUP_TIME) performs worse than getaddrinfo()
From: Bernhard Jaeger <B.Jaeger1_at_gmx.net>
Date: Mon, 25 Jun 2018 15:31:00 +0200
Received on 2018-06-25
Date: Mon, 25 Jun 2018 15:31:00 +0200
> Yes there is, but the question is if that stuff actually changes the
> measurement in any significant way and no there's no way to shut that off
> since that's the init stuff libcurl has to do to setup a transfer.
> For the purpose of researching this, it could be an idea to set an extra
> time-stamp just before the name resolve start just to see if that time ever
> actually is significant.
> measurement in any significant way and no there's no way to shut that off
> since that's the init stuff libcurl has to do to setup a transfer.
> For the purpose of researching this, it could be an idea to set an extra
> time-stamp just before the name resolve start just to see if that time ever
> actually is significant.
I have made some ECDFs with the data I have which were running on a VM with 8GB ram and 4 cores using libcurl 7.61.0.
I do seem to notice the initialisations.
But this data are from two different programs so it would be very helpful to have an additional timestamp within licurl to see if the initialisations are what really makes the difference here.
Would it be possible to have that feature on a new branch?
> If you use a libcurl using the threaded resolver backend, I think lots of the
> explanation is what sort of logic we use for the time-out based
> waiting/looping we do when we resolve the host name in a background thread
> without having a socket to wait for that gets triggered when the lookup is
> completed.
> explanation is what sort of logic we use for the time-out based
> waiting/looping we do when we resolve the host name in a background thread
> without having a socket to wait for that gets triggered when the lookup is
> completed.
Unfortunately I don't know what the threaded resolver backend is.
-- Bernhard Jaeger
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