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On Thu, Oct 16, 2003 at 07:19:51AM +0200, Jan-Benedict Glaw wrote: > On Wed, 2003-10-15 20:16:58 +0200, Gabriel Paubert <paubert@iram.es> > wrote in message <20031015181658.GA9652@iram.es>: > > On Wed, Oct 15, 2003 at 06:10:15AM -0700, William Lee Irwin III wrote: > > > On Tue, 2003-10-14 15:56:38 -0700, cliff white <cliffw@osdl.org> > > > Can you quantify the performance impact of cmov emulation (or whatever > > > it is)? I have a vague notion it could be hard given the daunting task > > > of switching userspace around to verify it. > > The other problem of the 386 is that it has a fundamental MMU flaw: > > no write protection on kernel mode accesses to user space, which makes > > put_user() intrinsically racy on a 386 and way more bloated when it is > > inlined (access_ok has to call a function which searches the VMA tree). > > However, this problem exists since the very first hour. Linux once > really ran quite well on those machines... Yes, but VM sharing between threads was rather infrequent back then and you need shared VM to create the race. > > I've rebooted my P-Classic router last night. Maybe I can see (in two > weeks or in a month or the like...) why it slows down, even with 32MB > RAM... It might be related to the size-4096 memory leak others are reporting right now. I don't know, but it's not such a far-fetched hypothesis either. Gabriel - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||
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