* [PATCH iproute2-next] Makefile: pass -pipe to the compiler
@ 2019-06-11 18:05 Matteo Croce
2019-06-11 19:28 ` Stephen Hemminger
0 siblings, 1 reply; 3+ messages in thread
From: Matteo Croce @ 2019-06-11 18:05 UTC (permalink / raw)
To: netdev; +Cc: Stephen Hemminger, David Ahern
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 <mcroce@redhat.com>
---
Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 48f469b0..6c35e7c2 100644
--- a/Makefile
+++ b/Makefile
@@ -48,7 +48,7 @@ HOSTCC ?= $(CC)
DEFINES += -D_GNU_SOURCE
# Turn on transparent support for LFS
DEFINES += -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-CCOPTS = -O2
+CCOPTS = -O2 -pipe
WFLAGS := -Wall -Wstrict-prototypes -Wmissing-prototypes
WFLAGS += -Wmissing-declarations -Wold-style-definition -Wformat=2
--
2.21.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH iproute2-next] Makefile: pass -pipe to the compiler
2019-06-11 18:05 [PATCH iproute2-next] Makefile: pass -pipe to the compiler Matteo Croce
@ 2019-06-11 19:28 ` Stephen Hemminger
2019-07-14 16:36 ` Matteo Croce
0 siblings, 1 reply; 3+ messages in thread
From: Stephen Hemminger @ 2019-06-11 19:28 UTC (permalink / raw)
To: Matteo Croce; +Cc: netdev, David Ahern
On Tue, 11 Jun 2019 20:05:13 +0200
Matteo Croce <mcroce@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 <mcroce@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 :-)
Maybe allow "EXTRA_CFLAGS" to be passed to Makefile for those that
have a burning need for this.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH iproute2-next] Makefile: pass -pipe to the compiler
2019-06-11 19:28 ` Stephen Hemminger
@ 2019-07-14 16:36 ` Matteo Croce
0 siblings, 0 replies; 3+ messages in thread
From: Matteo Croce @ 2019-07-14 16:36 UTC (permalink / raw)
To: Stephen Hemminger; +Cc: netdev, David Ahern
On Tue, Jun 11, 2019 at 9:28 PM Stephen Hemminger
<stephen@networkplumber.org> wrote:
>
> On Tue, 11 Jun 2019 20:05:13 +0200
> Matteo Croce <mcroce@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 <mcroce@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
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