I measure a downgrade of more 35% download time. I tried also to enlarge the CURL_MAX_WRITE_SIZE to 256K - 4MB but it doesn't improve the times. I am trying now to upgrade libssh2 to 1.7.0. Although I encounter some compilation errors (is there a specific Visual Studio version that is recommended for it?) I feel it will take me less time than trying to find the problem during debugging.
Thanks, On Sun, May 15, 2016 at 12:45 PM, Daniel Stenberg <[email protected]> wrote: > On Sun, 15 May 2016, Moti Avrahami wrote: > > I recently upgraded my libcurl version from 7.19.4 to 7.47.1 and I noticed >> that there is a performance downgrade when downloading files from SFTP >> servers than the older libcurl version. >> >> I checked both versions against the same SFTP servers. >> >> I use libssh2 version 1.4.1. >> >> Does anyone know what is reason and how can I fix it? >> > > I don't know the reason. But you're doing a *massive* upgrade bump so > almost everything has been changed internally. Clearly at some point the > SFTP performance got worse. How big is the speed difference you measure? > What's the latency to the server in your test case? > > You're also using an outdated libssh2 version. It has improved through > time and modern versions should be faster and more reliable. > > The way to track this down is through good old fashioned debugging. You > can possibly bisect yourself to the actual offending commit (assuming it > was a single specific one) and based on knowing which change it was we can > perhaps find the culprit/explanation faster. > > I've written about (poor) SFTP performance in libcurl several times in the > past and we have ideas on how it could be increased significantly, but > unfortunately nobody has yet actually converted any of those thoughts into > reality. One such mention is here: > https://curl.haxx.se/docs/todo.html#Modified_buffer_size_approach > > -- > > / daniel.haxx.se > ------------------------------------------------------------------- > List admin: https://cool.haxx.se/list/listinfo/curl-library > Etiquette: https://curl.haxx.se/mail/etiquette.html
------------------------------------------------------------------- List admin: https://cool.haxx.se/list/listinfo/curl-library Etiquette: https://curl.haxx.se/mail/etiquette.html
