https://bugzilla.kernel.org/show_bug.cgi?id=3094 --- Comment #21 from Artem S. Tashkinov <t.artem@xxxxxxxxxxxx> 2010-05-19 17:17:37 --- (In reply to comment #20) > I/O wait is measuring the amount of time the machine is waiting for the disk, > not how much it is using CPU. Disks haven't gotten much faster in the past ten > years (SSD aside) while processors dramatically did. There isn't a lot that can > be done about the speed of disks,. Getting the kernel to schedule I/O better > can help a bit but the fundamental problem is that a disk on a good day can > only really do about 200 operations/second. What really enrages people (and me too) is that under all circumstances CPU usage shown by `top` is always 100% whenever a single process is writing or reading to a spinning storage at full speed. It is _wrong_ and it is _misleading_ because then people think that the Linux kernel sucks at I/O operations, everyone instantly recollects Windows experience where (e.g. on my own PC) HDD access causes maximum 2% CPU usage. Fix the kernel idle time computation, otherwise people will keep complaining indefinitely. `cat /dev/sda > /dev/null` results in load average rapidly climbing to 1.32 and counting on my PC, that's just insane and wrong. -- Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
