Re: Fewer mallocs is better, episode #47

From: Henrik Holst via curl-library <curl-library_at_lists.haxx.se>
Date: Sat, 5 Feb 2022 00:38:00 +0100

Den fre 4 feb. 2022 kl 08:00 skrev Daniel Stenberg <daniel_at_haxx.se>:

> On Fri, 4 Feb 2022, Henrik Holst wrote:
>
> > Which leaves 53 strlen calls for curl.se and 490 for google.com, for
> curl.se
> > these are probably "no issue" but still no idea where the 490 ones for
> > google.com comes from (the traces only shows that strlen was called,
> not on
> > which string it was called so the digging is a bit time consuming).
>
> I suspect the reason for this difference might be the SAN name checks for
> the
> server certificate, since those name checks (when built to use OpenSSL)
> are
> done by curl code and the google.com servers have a rather large amount
> of
> names to check. See lib/hostcheck.c:Curl_cert_hostcheck()
>
Looks like for google.com half of them comes from the cert check,
hostmatch() is called 220 times for google.com and only 2 times for curl.se.

Half of those strlen calls (111 for google.com) can be easily removed and
I'll post a patch for that later. The remaining 109 for google.com and
hostmatch()
requires a very intrusive patch however since it would require to add a
size_t to struct hostname (aka add Howard Chu:s berval string) and that
struct is used _alot_
(which also means that there can be other winnings down the line besides
the certcheck since the hostname length is probably used a bit).

And then there are still about 3xx calls to strlen left for google.com that
as of yet have an unknown source.

/HH

>
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>
> / daniel.haxx.se
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Received on 2022-02-05