Date: Thu, 6 Nov 1997 23:24:16 -0800 (PST) From: Tom <tom@sdf.com> To: Joe McGuckin <joe@via.net> Cc: hackers@freebsd.org Subject: Re: Resolution of: 'sys' is consuming %50 of cpu Message-ID: <Pine.BSF.3.95q.971106232054.3176B-100000@misery.sdf.com> In-Reply-To: <199711070320.TAA11526@monk.via.net>
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On Thu, 6 Nov 1997, Joe McGuckin wrote: > After replacing the 3COM 3C509 with an Intel Etherexpress 100/B card, > system usage dropped from 75% to 30%. > > I've noticed something else: The load average hovers around 5-10. On the old > machine (200Mhz MMX Pentium) is stayed pegged at 50. The 300Mhz Pentium II > is supposed to be twice as fast as the 200Mhz MMX Pentium. I was expecting > load values in the 25-30 range. > > This makes me think that there's some kernel resource that I was running out > of - that once I hit that limit, the kernel would get bogged down. Not necessarily. The vx driver isn't so great, and it uses programmed I/O. It is probably blocking too long while communicating with the card, driving up the sys time. During this time, no user processes are running, driving up the load average as many processes become runnable. The fxp driver uses DMA, so some card transactions can probably be handled without involving the CPU. > Joe Tom
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