On Tue, Feb 23, 2016 at 08:17:57AM -0500, Steven Rostedt wrote: > On Tue, 23 Feb 2016 13:49:15 +0100 > Peter Zijlstra <[email protected]> wrote: > > > On Mon, Feb 22, 2016 at 04:26:53PM -0500, Steven Rostedt wrote: > > > From: "Steven Rostedt (Red Hat)" <[email protected]> > > > > > > To have nanosecond output displayed in a more human readable format, its > > > nicer to convert it to a seconds format (XXX.YYYYYYYYY). The problem is > > > that > > > to do so, the numbers must be divided by NSEC_PER_SEC, and moded too. But > > > as > > > these numbers are 64 bit, this can not be done simply with '/' and '%' > > > operators, but must use do_div() instead. > > > > Would not div_[us]64_rem() make more sense? It would typically result in > > just the one division, instead of two. > > The problem is, how do you do that in a printf() statement? > > We have "%llu.%09ul" which is two arguments in the printf(). And the > values we are processing can't be modified. Which is why the macro uses > ({ }) and creates a temp variable.
Hurm,. yes that's not something easily done. We need a temporary limited in scope to the printf statement, and C doesn't really do that.
