From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by el-out-1112.google.com with SMTP id y26so2851038ele.4 for ; Mon, 17 Mar 2008 19:19:20 -0700 (PDT) Message-ID: <70b6f0bf0803171919t9ba6cbewbc03c9ddae63c255@mail.gmail.com> Date: Mon, 17 Mar 2008 19:19:19 -0700 From: "Valerie Henson" Subject: Re: ebizzy performance with different allocators In-Reply-To: <200803172321.31572.nickpiggin@yahoo.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200803172321.31572.nickpiggin@yahoo.com.au> Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: opensource@google.com, Jakub Jelinek , linux-mm@kvack.org, "Rodrigo Rubira Branco (BSDaemon)" List-ID: [Cc'd current ebizzy maintainer, Rodrigo.] On Mon, Mar 17, 2008 at 5:21 AM, Nick Piggin wrote: > Hi, > > I was recently interested in ebizzy performance, and specifically the > reason why Linux doesn't appear to scale very well versus FreeBSD. [snip] > linux-glibc was the best single-threaded performer, with ~7000 r/s, > however it starts running into system time which the profile shows up > as unmapping pages and faulting in new pages. Is "fixing" this as simple > as increasing hysteresis in glibc? Can that be done via environment? (I > couldn't work out a way). Huh, yeah, that sounds like glibc is mmap()'ing your allocations. Check to see if your glibc version includes this patch: http://www.valhenson.org/patches/dynamic_mmap_threshold If it does, you shouldn't see much in the way of mmap/munmap activity when running ebizzy. It's possible that some other malloc() settings are interfering, maybe the trim threshold. It's also worth noting that the self-tuning mmap threshold is disabled if the user sets the mmap threshold explicitly. Oh, and is this 32-bit or 64-bit? If you want to tune the exact behavior of malloc with regard to mmap, check out: http://www.gnu.org/software/libtool/manual/libc/Malloc-Tunable-Parameters.html If you use the "-M" option to ebizzy, it will use mallopt() to turn off mmap()'d allocations entirely. (It'd be nice to have command line knobs for all the mallopt() tuning options, actually.) -VAL -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org