Date: Mon, 7 Feb 2011 15:58:01 -0500 From: Jung-uk Kim <jkim@FreeBSD.org> To: freebsd-threads@freebsd.org Cc: davidxu@freebsd.org Subject: Re: [RFC] Implement pthread_getthreadid_np(3) and pthread_getunique_np(3) Message-ID: <201102071558.03573.jkim@FreeBSD.org> In-Reply-To: <20110207202034.GS78089@deviant.kiev.zoral.com.ua> References: <201102041409.12314.jkim@FreeBSD.org> <201102071331.54198.jkim@FreeBSD.org> <20110207202034.GS78089@deviant.kiev.zoral.com.ua>
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On Monday 07 February 2011 03:20 pm, Kostik Belousov wrote: > On Mon, Feb 07, 2011 at 01:31:42PM -0500, Jung-uk Kim wrote: > > On Saturday 05 February 2011 04:58 am, Kostik Belousov wrote: > > > On Sat, Feb 05, 2011 at 02:24:09AM -0500, Jung-uk Kim wrote: > > > > On Friday 04 February 2011 04:33 pm, Kostik Belousov wrote: > > > > > On Fri, Feb 04, 2011 at 02:09:10PM -0500, Jung-uk Kim wrote: > > > > > > Our pthread_t is not an integral type and it causes a lot > > > > > > of trouble porting some software, which relies on Linux's > > > > > > gettid() or similar syscalls: > > > > > > > > > > > > http://www.kernel.org/doc/man-pages/online/pages/man2/get > > > > > >tid. 2.ht ml > > > > > > > > > > > > For example: > > > > > > > > > > > > http://docs.freebsd.org/cgi/mid.cgi?201102032111.13479.jk > > > > > >im > > > > > > > > > > > > To solve this problem, I implemented two functions: > > > > > > > > > > > > http://people.freebsd.org/~jkim/thr_tid.diff > > > > > > > > > > > > Basically, they are AIX's pthread_getthreadid_np(3) and > > > > > > pthread_getunique_np(3) look-alikes: > > > > > > > > > > > > http://publib.boulder.ibm.com/infocenter/iseries/v5r4/top > > > > > >ic/a pis/ users_22.htm > > > > > > http://publib.boulder.ibm.com/infocenter/iseries/v5r4/top > > > > > >ic/a pis/ users_23.htm > > > > > > > > > > > > Please let me know what you think. > > > > > > > > > > Why do you need new functions available in stubs ? > > > > > > > > Oops, my bad. Fixed: > > > > > > > > http://people.freebsd.org/~jkim/thr_tid2.diff > > > > > > > > > Also, would it be better to return proper id even if > > > > > threading is not initialized, instead of EINVAL ? > > > > > > > > Because I want it to be fast and cause no side-effect, no. > > > > > > You can allocate static lwpid_t self_tid variable, and in case > > > threading is not initialized yet, and self_tid == 0, do > > > self_tid = thr_self(). Otherwise, if threading is initialized > > > and self_tid != 0, return self_tid. > > > > > > BTW, what should be the behaviour of new functions after fork() > > > ? Is it undefined ? > > > > Please ignore this RFC. I found (undocumented) thr_self(2) works > > just like pthread_getthreadid_np(3) and I don't have immediate > > need for pthread_getunique_np(3). > > I think that making thr_* private libthr syscalls part of the > public namespace was unfortunate. If you need the functionality of > pthread_getthreadid_np(3), then please introduce it, as discussed > above, and use. > > We already have somewhat sad experience with kse, when static > binaries where broken. Using thr_self() directly in such important > application as jdk/jre might cause similar problem in future (I > hope not). > > Also, you said that pthread_getthreadid_np(3) was taken from AIX, > am I remember right ? This is additional argument for use it > instead of single-implementation interface. Agreed. http://people.freebsd.org/~jkim/thr_tid3.diff Please note pthread_getunique_np() is removed. Thanks, Jung-uk Kim
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