Now that [1]the Linux kernel has been removing Intel 486 CPU support and also proceeding to drop other vintage CPUs like the [2]AMD K5 CPU support and [3]AMD Elan , the Linux kernel is ready to make the TSC support unconditional for x86 processors.

The x86 Time Stamp Counter (TSC) has been around since the Intel Pentium days for counting the number of CPU cycles since its last reset. This high-resolution, low-overhead means of CPU timing information has been optional given that until recently the Linux x86 CPU support has extended to the i486 processors and others lacking TSC. But now thanks to removing those historical artifacts from the kernel, TSC always present for x86 can be safely assumed.

Thus [4]this patch in tip/tip.git's "x86/cpu" branch makes TSC support unconditional for x86 kernel builds. Separate to that Kconfig patch to make TSC unconditional, the non-TSC code paths will now be separately stripped out from the Linux kernel.

This is just one part of the broader effort of allowing more code cleaning and streamlining now that the very old and outdated i486 era processor support is phased out. With this unconditional TSC patch now in a TIP branch ahead of the Linux 7.2 merge window, expect it to be merged for that next kernel cycle.



[1] https://www.phoronix.com/news/Linux-7.1-Begins-Removing-i486

[2] https://www.phoronix.com/news/AMD-K5-CPUs

[3] https://www.phoronix.com/news/AMD-Elan-Linux-Driver-Removal

[4] https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?h=x86/cpu&id=111cbb4596e336373ab93e202918f4cdbf78a4c3