Date: Tue, 18 Nov 2003 21:50:41 -0800 (PST) From: Don Lewis <truckman@FreeBSD.org> To: drosih@rpi.edu Cc: current@FreeBSD.org Subject: Re: Unfortunate dynamic linking for everything Message-ID: <200311190550.hAJ5ofeF092376@gw.catspoiler.org> In-Reply-To: <p0600202dbbe06aca44fc@[128.113.24.47]>
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On 18 Nov, Garance A Drosihn wrote: > At 8:07 AM -0500 11/18/03, dyson@iquest.net wrote: > >> If there hadn't been a noticed increase in cost by using >> all-shared-libs, then the measurements were done >> incorrectly. If the decision is made based upon allowing >> for 1.5X (at least) times increase in fork/exec times, and >> larger memory usage (due to sparse allocations), ... > > I do remember some comments about benchmarks, and it was > true that the all-dynamic bin/sbin does come out slower. I > don't remember if the benchmarks were ours or from NetBSD's > investigation. However, I think we measured increase in > overall time for some set of commands, instead of "increase > in the fork() routine". Thus, the penalty observed was much > less than 50%. I think it was under 2%, but I don't remember > the exact number. When we're dealing with a 100% increase > in the cost of compiling something with the newer gcc, the > increase due to this change seemed pretty insignificant... I thought there were some NetBSD benchmark numbers posted, but after digging through my mail archives, I now think the results that I'm remembering were posted by Gordon and were run with rcNG, which is somewhat more shell intensive than our previous rc system: On 2 Jun, Gordon Tetlow wrote: > I'm planning on making a dynamically-linked root partition by 5.2. To > that end, I'm planning on doing to the following: > > Integrate Tim Kientzle's /rescue patches into the tree > Create /lib and populate with all the libs needed to support dynamically > linked binaries in /bin and /sbin > Have a big (probably NO_DYNAMIC_ROOT) knob to switch from static to > dynamic. > > There will be a performance hit associated with this. I did a quick > measurement at boot and my boot time (from invocation of /etc/rc to > the login prompt) went from 12 seconds with a static root to 15 > seconds with a dynamic root. I have yet to perform a worldstone on > it. I was thinking the difference was smaller than that.
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