Date: Mon, 2 Jul 2007 14:54:39 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-arch@freebsd.org Cc: arch@freebsd.org Subject: Re: wakeup_flags patch. Message-ID: <200707021454.39923.jhb@freebsd.org> In-Reply-To: <20070701160540.Y552@10.0.0.1> References: <20070701160540.Y552@10.0.0.1>
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On Sunday 01 July 2007 07:08:35 pm Jeff Roberson wrote: > http://people.freebsd.org/~jeff/wakeupflags.diff > > It didn't workout very cleanly since the flags have to go through three > layers. I could define wakeup and sleepq flags to be the same and skip a > bunch of conditionals. However, we'd then have to know which flags were > free to use in each case. Are there any further opinions on the style? > > This patch does not include an implementation for WAKEUP_LOCAL. I'm still > working on that in SCHED_SMP. Ironically, it does include an > implementation for WAKEUP_TAIL, however, I don't have any users of that. > :-) You can find the pre-threadlock patch for 7.x of what Y! uses for accept() at www.freebsd.org/~jhb/patches/justone.patch It has two features your WAKEUP_TAIL doesn't have (one of which I mentioned earlier): 1) it doesn't wakeup threads from swapped out processes (you aren't getting a thread that is "hot" in the cache if you have to go page it back in from disk), and 2) it returns a success/fail to the caller so that it can fallback to its traditional behavior if we couldn't find a "hot" thread to resume. -- John Baldwin
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