On Wed, Sep 14, 2016 at 03:53:32PM -0300, Paulo Zanoni wrote: > Em Qua, 2016-09-14 às 13:10 +0100, Dave Gordon escreveu: > > Commentary from Chris Wilson's original version: > > > > > > > > I was looking at some wait_for() timeouts on a slow system, with > > > lots of > > > debug enabled (KASAN, lockdep, mmio_debug). Thinking that we were > > > mishandling the timeout, I tried to ensure that we loop at least > > > once > > > after first testing COND. However, the double test of COND either > > > side > > > of the timeout check makes that unlikely. But we can do an > > > equivalent > > > loop, that keeps the COND check after testing for timeout (required > > > so > > > that we are not preempted between testing COND and then testing for > > > a > > > timeout) without expanding COND twice. > > > > > > The advantage of only expanding COND once is a dramatic reduction > > > in > > > code size: > > > > > > text data bss dec hex > > > 1308733 5184 1152 1315069 141 > > > 0fd before > > > 1305341 5184 1152 1311677 140 > > > 3bd after > > > > but it turned out that due to a missing iniitialiser, gcc had "gone > > wild trimming undefined code" :( This version acheives a rather more > > modest (but still worthwhile) gain of ~550 bytes. > > > > Signed-off-by: Dave Gordon <david.s.gordon@xxxxxxxxx> > > Original-idea-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > Cc: Zanoni, Paulo R <paulo.r.zanoni@xxxxxxxxx> > > Reviewed-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> Thanks for the improvement and review, pushed. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
