What HZ value out of {100,1000} is preferable (if one is not willing
to put in question the operating system itself) ?
Well, picking wrong value will have undesired side effect, most notably commands timing out earlier than they should have or "never" timing out. The right value varies from platform to platform, and I mean from Linux on one hardware platform to Linux on another hardware platfrom. Meaning that if you choose value of 100, which is suitable for i[3456]86 and hard-code it, you ought to keep compiling your application on i[3456]86 for all eternity. So what's wrong with asking OS, e.g. with sysconf(_SC_CLK_TCK)? A.