Messages in this thread | | | From | (H. Peter Anvin) | Subject | Re: 2.2.1 loosing 2 ticks: switching virtual console | Date | 8 Mar 1999 16:05:07 GMT |
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Followup to: <CF6F5640DAC@rkdvmks1.ngate.uni-regensburg.de> By author: "Ulrich Windl" <ulrich.windl@rz.uni-regensburg.de> In newsgroup: linux.dev.kernel > > Hello, > > I've found out that thekernel looses many ticks when I switch the > virtual console using Alt+Fx. It could be the key combination, or it > could be the console switching per se. I don't know which, but maybe > someone can find it easily. > > (I have been working in X11 for hours, and no multiple lost ticks > occured, but when I switchd virtual consoles, many of them appeared > within few minutes) >
I believe console switching is done with interrupts disabled. This is a high-overhead operation (especially with a graphic console) with obvious consequences.
However, something I don't seem to understand is why at least not machines with a TSC are taught to handle missing ticks. On non-TSC machines this information is typically not available, but TSC machines should be able to see missing ticks by examining the TSC.
-hpa -- "Linux is a very complete and sophisticated operating system. There are, and will be, large numbers of applications available for it." -- Paul Maritz, Group Vice President for Platforms And Applications, Microsoft Corporation [Reference at: http://www.kernel.org/~hpa/ms.html]
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