Messages in this thread | | | Date | Fri, 23 Oct 2009 12:18:41 +0200 (CEST) | From | John Kacur <> | Subject | Re: [performance problem] CONFIG_DYNAMIC_FTRACE: Increased kernel build times |
| |
2009/10/23 Ingo Molnar <mingo@elte.hu> wrote: > > Steve, > > i did an 64-bit allyesconfig build test (with debug_info disabled), with > and without CONFIG_DYNAMIC_FTRACE set. > > The build time results are: > > -CONFIG_DYNAMIC_FTRACE: 266.30 > +CONFIG_DYNAMIC_FTRACE: 296.07 (+11.2%) > > So we get more than 10% build time overhead. > > That's quite high - higher than what i remember having measured > originally when the first iteration of the mcount code went in. > > This extra overhead comes from the mcount post-processing script > (scripts/recordmcount.pl) that runs objcopy as well and is written in > Perl. I think this whole angle needs to be improved - 10% is way too > high of a price to pay.
Hi Ingo, do you still have the profiling data to share with us? Was the problem more in objcopy / objdump, rather than in the perl script itself?
Thanks
John | |