Jiffies are the internal timeunits of the Linux kernel. This is based on the HZ definition that you can find in /usr/include/asm/param.h on your own system, and differs from different hardware architectures. For example, on the i386 system this is set to 1/100s, and on the Alpha hardware it is set to 1/1024s. For a complete listing of the different values on different hardware architectures, see below.
Table A-1. Jiffies on different hardware
| Architecture | Jiffies | Notes |
|---|---|---|
| Alpha | 1024 | It seems to me that only AlphaServer 1200, 4000 and 4100 are set to 1024, if CONFIG_ALPHA_RAWHIDE is configured. If CONFIG_ALPHA_RAWHIDE is not set, then HZ is set to 1200. If anyone knows for sure about this, they are welcome to contact me. |
| ARM | 100 | |
| CRIS | 100 | |
| i386 | 100 | |
| ia64 | 1024 | Unless CONFIG_IA64_HP_SIM is configured. Then HZ is defined to 32 since we will then simulate ia64 architecture, which is slow. |
| m68k | 100 | |
| MIPS | 100 | You should better read the source of include/asm/param.h, since this value vary quite a lot based on what kind of hardware you are running. |
| MIPS64 | 100 | |
| PA-RISC | 100 | |
| PPC | 100 | |
| PPC-64 | 100 | Once again, if you run this hardware, read the include/asm/param.h to fully understand this value. |
| S390 | 100 | |
| S390X | 100 | |
| SH | 100 | |
| Sparc | 100 | |
| Sparc64 | 100 |