From mboxrd@z Thu Jan 1 00:00:00 1970 From: Duraid Madina Date: Wed, 30 Jan 2002 05:48:36 +0000 Subject: [Linux-ia64] What's taking all the system time..? Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Hi guys, I've got a big (production) code that depends on a simple 'graph' library in C++. To try it out on Itanium, I stripped it down and whipped up a tiny 'benchmark' of the graph library. When I tried this on an Itanium system here (2.4.9-SMP, gcc/g++ 2.96/3.0.3 and intel c++ 6.0) the code runs for about 30 seconds, 20 of which is reported as 'system' time. The thing is, this is (supposed to be) a CPU-bound job: on my home x86 system, it runs in about 3 seconds, and with negligible system time. 'top' and 'time' show the gobs of system time being used, but 'strace' picks up nothing out of the ordinary (0.014 seconds system time, dominated by calls to brk() (this is expected). I'm hoping someone with a spare moment could try and reproduce this, and perhaps let me know what's going on? Right now, I'm guessing libc brokenness on ia64, but perhaps it's VM suckage? :\ Alas, on the box I have access to, I can't profile the code because adding -pg when compiling leads to a binary that segfaults at startup (ditto with the Intel compiler, so i'm guessing the profile libraries are borked). You can grab the source (18kB) here: http://www.idesign.fl.net.au/why_systime/why_systime.tar.gz just 'make' (be sure 'gcc' and 'g++' point to a recent enough version of gcc/g++ - preferably 3.0 or later) and then run 'a.out'. Lost, Duraid