Commits
Denys Vlasenko committed ab507c9a54c
e1000e: e1000e_cyclecounter_read(): do overflow check only if needed SYSTIMH:SYSTIML registers are incremented by 24-bit value TIMINCA[23..0] er32(SYSTIML) are probably moderately expensive (they are pci bus reads). Can we avoid one of them? Yes, we can. If the SYSTIML value we see is smaller than 0xff000000, the overflow into SYSTIMH would require at least two increments. We do two reads, er32(SYSTIML) and er32(SYSTIMH), in this order. Even if one increment happens between them, the overflow into SYSTIMH is impossible, and we can avoid doing another er32(SYSTIML) read and overflow check. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Tested-by: Aaron Brown <aaron.f.brown@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>