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Progresss Bar performance bug in Windows

From: Doughty, Marc <>
Date: Mon, 29 Jul 2013 13:41:28 -0400

     I'm using cURL in a script on Windows 8. The script runs in Powershell
and downloads very large files via HTTP. When I set the '--progress-bar'
option, I noticed that the download was slow, the CPU usage was very high
(one core @ 100%), and that the progress bar itself appeared to be
'flickering' in the console window. Switching to normal operation fixed the
problem, but I want my users to see the progress bar and not other download
     I'm sure there are plenty of ways to reduce the amount of 'drawing'
that's happening. Could the progress bar only update the console when
there's enough to 'bump up one step', or possibly at a certain timed
interval that would be 'polite' to system resources?

Here's a dump of 'curl.exe -V':

curl 7.31.0 (i386-pc-win32) libcurl/7.31.0 OpenSSL/1.0.0k zlib/1.2.8
libidn/1.18 libssh2/1.4.3 librtmp/2.3
Protocols: dict file ftp ftps gopher http https imap imaps ldap pop3 pop3s
rtmp rtsp scp sftp smtp smtps telnet tftp
Features: AsynchDNS GSS-Negotiate IDN Largefile NTLM SSL SSPI libz

and the PowerShell command I am invoking from is this:

# Start-Process "curl.exe" -Wait -NoNewWindow -ArgumentList

Also, my PowerShell session is logged using 'Start-Transcript'

- Marc Doughty
"If you aren't sure who is the give-way vessel, you are the give-way

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Received on 2013-07-29

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