From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 09 Jul 2002 09:08:35 -0700 From: "Martin J. Bligh" Subject: Re: scalable kmap (was Re: vm lock contention reduction) Message-ID: <134700000.1026230915@flay> In-Reply-To: <3D2A7466.AD867DA7@zip.com.au> References: <3D2A55D0.35C5F523@zip.com.au> <1214790647.1026163711@[10.10.2.3]> <3D2A7466.AD867DA7@zip.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Andrea Arcangeli , Linus Torvalds , Rik van Riel , "linux-mm@kvack.org" List-ID: >> I can dig out the whole acg, and see what was calling copy_strings, >> that might help give us a clue. > > Well, it'll be exec(). Yup ;-) 0.95 18.17 30186/90554 copy_strings_kernel [68] 1.90 36.34 60368/90554 do_execve [15] [36] 1.5 2.85 54.52 90554 copy_strings [36] 40.55 0.00 2274831/2528191 _generic_copy_from_user [41] 6.88 0.21 2274831/3762429 kmap_high [87] 4.15 0.00 2274831/3762429 kunmap_high [105] 2.12 0.00 2273886/4517587 strnlen_user [120] 0.09 0.51 31139/4284514 _alloc_pages [24] 0.00 0.00 31139/4284514 alloc_pages [369] 0.00 0.00 2/30186 load_script [553] 0.00 19.12 30184/30186 do_execve [15] [68] 0.5 0.00 19.12 30186 copy_strings_kernel [68] 0.95 18.17 30186/90554 copy_strings [36] > Updated patch below. We don't need an atomic kmap in copy_strings > at all. kmap is the right thing to do, but just be smarter about it. > Hanging onto the existing kmap in there reduces the number of kmap() > calls by a factor of 32 across a kernel compile. Sounds about right, looking at the data above. > But still no aggregate speedup. Now that really is odd. Will get you some more numbers. M. -- 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/