On Wed, Aug 26, 2020 at 05:33:20PM +0100, Ferruh Yigit wrote: > On 7/14/2020 10:51 PM, Dharmik Thakkar wrote: > > Meson build system lacks support for > > CONFIG_RTE_TEST_PMD_RECORD_CORE_CYCLES and > > CONFIG_RTE_TEST_PMD_RECORD_BURST_STATS configuration options. > > > > One solution is to add these options within meson_options.txt > > > > Since adding these as runtime config causes no performance impact, > > Hi Dharmik, > > These are on the datapath, and even disable there will be additional > checks, isn't it expected to have some impact? Did you do any > measurements for it? > Branches that always predict the same way can be very cheap, and unless proven to be a problem, I'd see no issue with having a few on the datapath - especially if it just one or two per burst. If we start seeing a significant number, or ones that occur for every packet, then we perhaps need to be more cautious.
I also think that using lots of different CFLAGS for turning things on and off is as bad - or even worse - than using the old build-time config options, just this time we don't have a single list of them somewhere! Therefore, I think we really need to start converting these to runtime options where we can. Regards, /Bruce
