Using the following, we noticed that the process is cpu bound at close to 100% and transfer time drops from 300MBytes/sec to 7Mbytes/sec for a 10GiB file.

curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, 1L);
curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, 30L);

Looking at pstack, it is spending almost all its’ time in:

#0 0x00007f7be042503a in curlx_tvdiff () from /opt/quantum/curl/lib/libcurl.so.4
#1 0x00007f7be044d126 in multi_addtimeout () from /opt/quantum/curl/lib/libcurl.so.4
#2 0x00007f7be044d2e5 in Curl_expire () from /opt/quantum/curl/lib/libcurl.so.4
#3 0x00007f7be043d886 in Curl_speedcheck () from /opt/quantum/curl/lib/libcurl.so.4
#4 0x00007f7be04477b8 in Curl_readwrite () from /opt/quantum/curl/lib/libcurl.so.4
#5 0x00007f7be044e82a in multi_runsingle () from /opt/quantum/curl/lib/libcurl.so.4
#6 0x00007f7be044f445 in curl_multi_perform () from /opt/quantum/curl/lib/libcurl.so.4
#7 0x00007f7be04487ae in curl_easy_perform () from /opt/quantum/curl/lib/libcurl.so.4

Is this a bug or are we using the wrong options etc.

Thanks.

Colin Ngam

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Received on 2013-12-07