Date: Thu, 3 May 2007 10:30:43 -0700 From: Alfred Perlstein <alfred@freebsd.org> To: Robert Watson <rwatson@FreeBSD.org> Cc: cvs-src@FreeBSD.org, Randall Stewart <rrs@cisco.com>, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern uipc_debug.c uipc_sockbuf.c uipc_socket.c uipc_syscalls.c src/sys/netinet sctputil.c src/sys/sys socketvar.h Message-ID: <20070503173043.GM67243@elvis.mu.org> In-Reply-To: <20070503180707.D30997@fledge.watson.org> References: <200705031442.l43Egggi064069@repoman.freebsd.org> <463A0198.3040507@cisco.com> <20070503160413.GL67243@elvis.mu.org> <20070503180707.D30997@fledge.watson.org>
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* Robert Watson <rwatson@FreeBSD.org> [070503 10:08] wrote: > > > > >Now process B is in an uninterruptable wait until the remote side drains > >the pipe. > > > >The same problem might happen (even easier to reproduce) when there are > >multiple readers. > > > >Of course this all depends on me missing something. > > > >Can you explain? > > You are entirely right -- I'm not sure how I missed the SB_NOINTR flag > semantics in sb_lock(), but apparently I did. I'm talking to Attilio right > now about adding an interruptible version of the sleeping exclusive lock > acquire and will follow up on this shortly. Thanks for pointing this out! OK, please do your usual awesome benchmarking though so that this potential fix doesn't wind up being a performance pessimizing stopgap. I'm somewhat surprised that an attempt to move from sleep to cv based rendevous wasn't attempted first. -- - Alfred Perlstein
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