On Wed, 16 Jul 2014, David Meyer wrote:
Profiling shows that curl_multi_perform() is spending all its time in
Curl_multi_process_pending_handles(). This function is called every time a
request completes, and it iterates over every running request.
Ugh, yes. That's not very nice. A linear scan over all attached easy
handles...
I am able to completely eliminate the performance problem by commenting out
the body of Curl_multi_process_pending_handles(). It appears this code is
only needed when CURLMOPT_MAX_TOTAL_CONNECTIONS is set.
The functionality is for pipelining so it should only be necessary if
pipelining is enabled on the multi handle.
Are you using pipelning?
Would it make sense to store the list of pending handles as a separate
linked list, to avoid iterating through every easy_handle?
Yes!
It should actually do both I think: only scan for such a handle if pipelining
is enabled, and use a separate list of pending handles so that it never has to
scan through all handles for this.
--
/ daniel.haxx.se
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