On Tue, Jun 11, 2019 at 9:28 PM Stephen Hemminger <step...@networkplumber.org> wrote: > > On Tue, 11 Jun 2019 20:05:13 +0200 > Matteo Croce <mcr...@redhat.com> wrote: > > > Pass the -pipe option to GCC, to use pipes instead of temp files. > > On a slow AMD G-T40E CPU we get a non negligible 6% improvement > > in build time. > > > > real 1m15,111s > > user 1m2,521s > > sys 0m12,465s > > > > real 1m10,861s > > user 1m2,520s > > sys 0m12,901s > > > > Signed-off-by: Matteo Croce <mcr...@redhat.com> > > Why bother, on my machine (make -j12). > > Before > real 0m6.320s > user 0m30.674s > sys 0m3.649s > > > After (with -pipe) > real 0m6.158s > user 0m31.197s > sys 0m3.532s > > > So it is slower. Get a faster disk :-) >
I did it :) root@apu:~# hdparm -t /dev/sda /dev/sda: Timing buffered disk reads: 1086 MB in 3.00 seconds = 361.58 MB/sec No change at all thought. It's really a CPU bound job, and this machine is not a number cruncher: root@apu:~# dd if=/dev/zero bs=1G count=1 status=none |time -p sha1sum 2a492f15396a6768bcbca016993f4b4c8b0b5307 - real 16.00 user 12.38 sys 2.05 I think that the slight increase is due to the fact that the processes starts in parallel, instead of being serialized. > Maybe allow "EXTRA_CFLAGS" to be passed to Makefile for those that > have a burning need for this. Just out of curiosity, I checked the linux history repo to discover when it was introduced in the kernel, it tooks me a while to really find it: Linux-0.99.13k (September 19, 1993) -- Matteo Croce per aspera ad upstream
