> -----Original Message----- > > > From: Dan Carpenter [mailto:dan.carpenter@xxxxxxxxxx] > > > Sent: Tuesday, July 8, 2014 17:27 PM > > > To: Dexuan Cui > > > Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > driverdev- > > > devel@xxxxxxxxxxxxxxxxxxxxxx; plagnioj@xxxxxxxxxxxx; > > > tomi.valkeinen@xxxxxx; linux-fbdev@xxxxxxxxxxxxxxx; olaf@xxxxxxxxx; > > > apw@xxxxxxxxxxxxx; jasowang@xxxxxxxxxx; Haiyang Zhang > > > Subject: Re: [PATCH v2] video: hyperv: hyperv_fb: refresh the VM screen > by > > > force on VM panic > > > > > > Don't use likely/unlikely unless you have benchmark numbers to show > that > > > it makes a speed up. > > > > > > regards, > > > dan carpenter > > > > Hi Dan, > > Here the variable 'synchronous_fb' is only set to true when the system > panics. > > So before the system panics, it's always 'unlikely'. :-) > > Then take advantage of gcc's and your processor's prediction, which > knows that 0 is the "common" case and will choose to do the right thing > here. > > Dan is right, never put those markings in your code unless you can > benchmark the difference. Which means in reality, never put them in > your code. > > gerg k-h OK, let me send out a v3 patch, which will remove the unlikely. Thanks, -- Dexuan -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
