Re: python readlines() is slow when run in an apache2 cgi running in a vserver
So, I finally solved my problem[1]. Darcsweb was slow under vserver because python dup2 is slow when ulimit -H -n is high : closing all those fd's in a python loop is slow, see Lib/popen2.py in the python source that says : for i in xrange(3, MAXFD): try: os.close(i) And in a vserver, the default ulimit -H -n which is RLIMIT_NOFILE is 1024^2. This means that MAXFD is also 1024^2 and that the loop is long. This does not happen on a Gentoo box because the gentoo apache2 initscript does not use apache2ctl whereas debian does. And because of this magic line in /usr/sbin/apache2ctl : ULIMIT_MAX_FILES=ulimit -S -n `ulimit -H -n` soft limits become hard and apache gains 1024^2 max fd's. Thanks to the good guys at #vserver irc channel, I fixed my slowness doing : echo 1024 /etc/vservers/guest/ulimits/nofile.hard I still do not know where this 1024 on the host or this 1024^2 on the guest come from, but my problem is fixed. Cheers everybody, Alexandre [1] http://lists.debian.org/debian-user/2007/01/msg02688.html -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
python readlines() is slow when run in an apache2 cgi running in a vserver
Hi, I'm just clueless with one particular behavior of the readlines function. I've written a sample program that illustrates this prehaps bug I'm encountering. The box I used for this is an AMD Sempron 2800+ with 256 Mb of RAM : - When run on this standard etch box as a cgi script in apache2, it runs in less than a second. - When run in a vserver guest on this standard etch box from the commandline, it runs in less than a second. When run in a vserver guest on this standard etch box as a cgi script in apache2, it takes 7 seconds to complete! During this time, CPU usage is 100%. A friend of mine cannot reproduce on a Gentoo box with a similar setup. Updating vserver and the kernel to the latest version does not fix the problem. Using a brand new vserver (using newvserver and aptitude install apache2, with standard conffiles) does not fix the issue. I've narrowed the problem to the readlines() function. Questions arise from this : - can I narrow it better than readlines(), perhaps in C/C++ ? - is this apache2's or vserver's fault although similar perl or php programs (i.e. that read input) do not have the same problem? - any ideas, advices on all this? Thanks in advance, Alexandre test.cgi Description: Binary data
