From: Vasily Gorbik <gor@linux.ibm.com>
To: Andi Kleen <ak@linux.intel.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>,
Michal Marek <michal.lkml@markovi.net>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-s390@vger.kernel.org
Subject: Re: [PATCH 2/4] trace: avoid calling cc-option -mrecord-mcount for every Makefile
Date: Tue, 7 Aug 2018 13:59:31 +0200 [thread overview]
Message-ID: <your-ad-here.call-01533643171-ext-1234@work.hours> (raw)
In-Reply-To: <20180806180740.GI4238@tassilo.jf.intel.com>
On Mon, Aug 06, 2018 at 11:07:40AM -0700, Andi Kleen wrote:
> On Mon, Aug 06, 2018 at 03:17:44PM +0200, Vasily Gorbik wrote:
> > Currently if CONFIG_FTRACE_MCOUNT_RECORD is enabled -mrecord-mcount
> > compiler flag support is tested for every Makefile.
>
> Good catch. Does it make a measurable compile time difference?
>
A bit more than couple of seconds, but it does make a difference for a
delta build:
with patch:
real 0m9.405s
user 0m6.966s
sys 0m2.287s
without:
real 0m12.153s
user 0m9.058s
sys 0m3.026s
with -j48 on s390 24 cores lpar:
with patch:
real 0m1.949s
user 0m7.034s
sys 0m2.400s
without:
real 0m2.255s
user 0m9.243s
sys 0m3.266s
> >
> > Top 4 cc-option usages:
> > 511 -mrecord-mcount
next prev parent reply other threads:[~2018-08-07 11:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-06 13:17 [PATCH 0/4] ftrace build improvements Vasily Gorbik
2018-08-06 13:17 ` [PATCH 1/4] trace: handle CC_FLAGS_FTRACE more accurately Vasily Gorbik
2018-08-06 13:17 ` [PATCH 2/4] trace: avoid calling cc-option -mrecord-mcount for every Makefile Vasily Gorbik
2018-08-06 18:07 ` Andi Kleen
2018-08-07 11:59 ` Vasily Gorbik [this message]
2018-08-06 13:17 ` [PATCH 3/4] trace: add -mcount-nop option support Vasily Gorbik
2018-08-06 13:17 ` [PATCH 4/4] s390/ftrace: add -mfentry and -mnop-mcount support Vasily Gorbik
2018-08-07 5:30 ` Heiko Carstens
2018-08-08 11:10 ` Vasily Gorbik
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