Date: Wed, 04 May 2011 16:18:11 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: lev@FreeBSD.org Cc: freebsd-stable@FreeBSD.org Subject: Re: How to understand, what userland program does in kernel? Message-ID: <4DC15213.2090602@FreeBSD.org> In-Reply-To: <455293202.20110504164901@serebryakov.spb.ru> References: <455293202.20110504164901@serebryakov.spb.ru>
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on 04/05/2011 15:49 Lev Serebryakov said the following: > Hello, Freebsd-stable. > > I have userland program (transmission BT client), which spent 100% > of one core of E4500 CPU when it has many peers. It is surprises me, > as channel is only 35Mbit, and my "Linux" friends can upload much more > on comparable hardware. > > But what surprises me even more, that 50% of this time it spends as > System time. > > Is here any way to understand, what transmission does in kernel for > so much time? It seems, that userland profiling doesn't help me, am I > right? ktrace can easily show you what system calls are made by your program and how much time they take. Maybe that would be sufficient for you. -- Andriy Gapon
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