From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 10 Jul 2002 15:43:20 -0700 From: "Martin J. Bligh" Subject: Re: scalable kmap (was Re: vm lock contention reduction) Message-ID: <91460000.1026341000@flay> In-Reply-To: <3D2BC6DB.B60E010D@zip.com.au> References: <3D2A55D0.35C5F523@zip.com.au> <1214790647.1026163711@[10.10.2.3]> <3D2A7466.AD867DA7@zip.com.au> <20020709173246.GG8878@dualathlon.random> <3D2BC6DB.B60E010D@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 , Andrea Arcangeli Cc: Linus Torvalds , Rik van Riel , "linux-mm@kvack.org" List-ID: > Here's the diff. The kmap() and kmap_atomic() rate is way down > now. Still no benefit from it all through. Martin. Help. Hmmm ... well I have some preliminary results on the 16-way NUMA for kernel compile, and it doesn't make things faster - if anything there's a barely perceptible slowdown (may just be statistical error). On the other hand, Hanna just did some dbench measurements on an 8-way SMP, and got about 15% improvement out of it (she mailed the results to lkml just now). The profile comparison between 2.4 and 2.5 is interesting. Unless I've screwed something up in the profiling, seems like we're spending a lot of time in do_page_fault (with or without your patch). It's *so* different, that I'm inclined to suspect my profiling .... (profile=2). 2.5: 46361 total 0.3985 36500 default_idle 570.3125 5556 do_page_fault 4.5653 1087 do_softirq 5.2260 673 pte_alloc_one 3.8239 529 schedule 0.5700 304 exit_notify 0.3800 192 __wake_up 1.7143 188 do_fork 0.0904 180 system_call 4.0909 174 pgd_alloc 2.7188 109 timer_bh 0.1548 2.4 + patches 22256 total 0.0237 13510 default_idle 259.8077 2042 _text_lock_swap 37.8148 585 lru_cache_add 6.3587 551 do_anonymous_page 1.6596 488 do_generic_file_read 0.4388 401 lru_cache_del 18.2273 385 _text_lock_namei 0.3688 363 __free_pages_ok 0.6927 267 __generic_copy_from_user 2.5673 222 __d_lookup 0.8672 211 zap_page_range 0.2409 188 _text_lock_dec_and_lock 7.8333 179 rmqueue 0.4144 178 __find_get_page 2.7812 161 _text_lock_read_write 1.3644 157 file_read_actor 0.6886 151 nr_free_pages 2.9038 123 link_path_walk 0.0478 118 set_page_dirty 1.2292 101 fput 0.4353 Interestingly, kmap doesn't show up in the virgin 2.5 profile at all, but it does in the 2.4 profile ... 7 flush_all_zero_pkmaps 0.0700 109 kmap_high 0.3028 -- 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/