The following reply was made to PR kern/131597; it has been noted by GNATS.
From: Konstantin Belousov <kostik...@gmail.com> To: John Baldwin <j...@freebsd.org> Cc: bug-follo...@freebsd.org, guilla...@morinfr.org, thera...@freebsd.org Subject: Re: kern/131597: [kernel] c++ exceptions very slow on FreeBSD 7.1/amd64 Date: Fri, 28 Jun 2013 20:17:21 +0300 --hhtCH1hro9pJkPIH Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jun 28, 2013 at 08:47:55AM -0400, John Baldwin wrote: > Looking at this again, the patch committed in 178807 is just wrong and sh= ould=20 > be reverted. There is no state in rtld that needs to be protected via a = write=20 > lock. GCC is too lazy to use their own locking to protect shared state= =20 > between threads and wants the runtime linker to enforce this. Their=20 > justification that glibc doesn't allow concurrent execution of this isn't= a=20 > valid excuse. For an API like this that just walks a list and invokes a= =20 > callback, if the callback manipulates shared state owned by the caller, t= he=20 > caller should be responsible for sychronizing access to it, not rtld! >=20 > Instead I think we should apply the patch in the original GCC bug to our = in- > tree GCC and to our GCC ports. This should remove the sigprocmask calls = and > not penalize other users of dl_iterate_phdr() for GCC's poor behavior. In other words, we should become knowingly incompatible with the stock GCC and with other consumers of dl_iterate_phdr(), like libunwind ? E.g. libunwind ability to unwind from the signal handler relies on this behaviour. --hhtCH1hro9pJkPIH Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (FreeBSD) iQIcBAEBAgAGBQJRzcUgAAoJEJDCuSvBvK1BBuwQAIWoFrFkw9Op7RybuuAw9K5h f49+JDpcscYrQcF8KSYWiUdV3ZcoBnubqKpT+6vWm5MQ4PwUCEv3ouKAhD/oe4n+ oJg3pQz+mFicI7s0Wr3rJFyf0vO5wcHnxDOq7XdjHIPlGqTZcnOjubdCJ42xpZkT 7004JA8B8WHitjh+9qJGQWOUDfBzUWDE3WwieqpYnKricnFhJh8/6gTg6abbZGkE 6szxxKdPMUHJ28X54HU1DV9A2TJgfjLsGIzneQtfpOp7TTIyTKfn2hFHp5eLhWB/ voH0HAegdg7ew3MaCl2fnGKb6UR0h3yShowp3KfH1LozmZNDw6C/6VSKwy55aSYY GaVXlWEhniim7NaRgP2okdMPEz07pUt3KoIN5mQGrlvgusTUa7YXcrwCm97l72dT EqjgffvFUPmmHP38jhgf/wkI1aQ6tY7eSqSLDM+MMBX6TnPKx4EAr3H/tc79idEx O89zUHFJPuI7YY563O+dR0Bm09kIDPVNb3hTG09JF2KCxY3QYlje8Iu5ndKOLCi+ HvFwnTLpDEFEd22oNWdSeNUq97Rr2mAMSv5dk9A+a8mtsRbzPSeuylIKSEEKquDu USJ2ZyISoTnZbb6Iz6SYkZRn8vOBRUfBbpPRcAJh2FkBTegl7JE7dS3tM7C26uzf MxGTc8YbAXTWA1XFxyZR =hwdp -----END PGP SIGNATURE----- --hhtCH1hro9pJkPIH-- _______________________________________________ freebsd-bugs@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "freebsd-bugs-unsubscr...@freebsd.org"
