From: David Sterba <dsterba@suse.cz>
To: Rongqing Li <rongqing.li@windriver.com>
Cc: linux-btrfs@vger.kernel.org, sandeen@redhat.com
Subject: Re: [PATCH] btrfs-progs: Add dependencies explicitly to fix a parallel build issue
Date: Mon, 23 Sep 2013 14:26:14 +0200 [thread overview]
Message-ID: <20130923122614.GN6810@suse.cz> (raw)
In-Reply-To: <523E429F.8010606@windriver.com>
On Sun, Sep 22, 2013 at 09:06:39AM +0800, Rongqing Li wrote:
> I want to know how many cores your cpu has? I can not reproduce it on
> my 2 cores cpu, but it always happens when run on a server which is
> a 16 cores cpu and "make -j20"
Depends on what you call a core, I've tested this on a box with 8 cpu
cores and 64 logical cpus. I can clearly see that the build is stalled
for a few moments at '[SH] version.h' before it proceeds to '[CC] ...'.
> >The dependency files are generated by an implicit rule .c -> .o.d, so
> >there should be no problem for any of the files listed above.
>
> Do you means the below:
>
> .c.o:
> $(Q)$(check) $<
> @echo " [CC] $@"
> $(Q)$(CC) $(DEPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c $<
Rather
%.o.d: %.c
$(Q)$(CC) -MM -MG -MF $@ -MT $(@:.o.d=.o) -MT $(@:.o.d=.static.o) -MT $@ $(AM_CFLAGS) $(CFLAGS) $<
the .o.d files are included at the end of Makefile, I'm not completely
sure that they get included before the .c.o rule is processed. That way
the .o.d files would be empty and the dependency on version.h missing.
david
prev parent reply other threads:[~2013-09-23 12:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-18 1:11 [PATCH] btrfs-progs: Add dependencies explicitly to fix a parallel build issue rongqing.li
2013-09-18 1:51 ` Eric Sandeen
2013-09-18 1:55 ` Rongqing Li
2013-09-23 7:17 ` Rongqing Li
2013-09-18 1:56 ` [PATCH] btrfs-progs: Add version.h dependency to fix parallel builds Eric Sandeen
2013-09-18 2:26 ` Eric Sandeen
2013-09-18 6:39 ` Rongqing Li
2013-09-18 14:51 ` [PATCH] btrfs-progs: Add dependencies explicitly to fix a parallel build issue David Sterba
2013-09-22 1:06 ` Rongqing Li
2013-09-23 12:26 ` David Sterba [this message]
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