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Message-ID: <20110630023306.GY2729@thunk.org> Date: Wed, 29 Jun 2011 22:33:06 -0400 From: Ted Ts'o <tytso@....edu> To: Sean McCauliff <Sean.D.McCauliff@...a.gov> Cc: "linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org> Subject: Re: High CPU Utilization When Copying to Ext4 On Wed, Jun 29, 2011 at 05:01:45PM -0700, Sean McCauliff wrote: > Sorry, I didn't mean to bother you. I did try and email ext3-users > so as to not take up any developer time with my question. Yeah, but it's not likely anyone on that list would be able to help you. Both ext3 and ext4 isn't expected to take a huge amount of CPU under normal conditions when doing this type of copying where you will be likely disk bound. Well, you're not using fallocate() (at least you haven't disclosed it to date), and writing into fallocated space is the only thing that would be using a workqueue at all (which is what the kworker threads are using). So I very much doubt it has anything to do with ext4. The fiber channel drivers do use workqueues a fair amount, so yes, it would be useful to know that you are using a fiber channel SAN. At this point I'd suggest that you use oprofile or perf to see where the CPU is being consumed. Perf is probably better since it will allow you to see the call chains. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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