Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269032AbUJENgR (ORCPT ); Tue, 5 Oct 2004 09:36:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269028AbUJENgR (ORCPT ); Tue, 5 Oct 2004 09:36:17 -0400 Received: from mail4.hitachi.co.jp ([133.145.228.5]:42404 "EHLO mail4.hitachi.co.jp") by vger.kernel.org with ESMTP id S269079AbUJENgA (ORCPT ); Tue, 5 Oct 2004 09:36:00 -0400 Message-ID: <4162A359.8030701@sdl.hitachi.co.jp> Date: Tue, 05 Oct 2004 22:36:25 +0900 From: Hideo AOKI Organization: Systems Development Lab., Hitachi, Ltd. User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; ja-JP; rv:1.4) Gecko/20030624 Netscape/7.1 (ax) X-Accept-Language: ja MIME-Version: 1.0 To: akpm@osdl.org, riel@redhat.com Cc: linux-kernel@vger.kernel.org Subject: [PATCH 2.6] vm-thrashing-control-tuning Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4822 Lines: 115 Hello, Token based thrashing control has a good effect in thrashing situation. In current implementation, token timeout is a fixed value as SWAP_TOKEN_TIMEOUT. I think that administrators can improve thrashing behavior if the value can be changed. This patch adds "swap_token_timeout" parameter in /proc/sys/vm. The parameter means expired time of token. Unit of the value is HZ, and the default value is the same as current SWAP_TOKEN_TIMEOUT (i.e. HZ * 300). The patch can be applied to both 2.6.9-rc2 and 2.6.9-rc3. I tested the patch on an IA-32 4 way machine which has 4GB memory. Based kernel was 2.6.9-rc1. I tested five swap_token_time_out values. I created 256 workload generation processes on the machine. Each process generated same workload: repeating random file writing and memory access (Memory region is 18MB). I ran the processes for one hour and calculated write throughput of workload processes. The result was following. swap_token_time_out Write throughput [MB/s] ------------------- ---------------------- 30,000,000 6.71 3,000,000 8.26 300,000 (DEFAULT) 7.90 30,000 8.16 3,000 7.43 As you can see, it may be possible to improve application performance according to tune swap_token_time_out. Additionally, I think it is better to decrease default value. One reason is that the other values gained good performance. The other is that behavior of kernel may be unstable if swap_token_time_out is too long. I am exploring tuning policy. Any comments or suggestions? Best regards, Hideo AOKI Systems Development Laboratory, Hitachi, Ltd. ---- Signed-off-by: Hideo Aoki diff -uprN linux-2.6.9-rc2/include/linux/swap.h linux-2.6.9-rc2-tbtc_tune/include/linux/swap.h --- linux-2.6.9-rc2/include/linux/swap.h 2004-09-15 12:20:40.000000000 +0900 +++ linux-2.6.9-rc2-tbtc_tune/include/linux/swap.h 2004-09-28 15:12:33.000000000 +0900 @@ -230,6 +230,7 @@ extern spinlock_t swaplock; /* linux/mm/thrash.c */ extern struct mm_struct * swap_token_mm; +extern unsigned long swap_token_default_timeout; extern void grab_swap_token(void); extern void __put_swap_token(struct mm_struct *); diff -uprN linux-2.6.9-rc2/include/linux/sysctl.h linux-2.6.9-rc2-tbtc_tune/include/linux/sysctl.h --- linux-2.6.9-rc2/include/linux/sysctl.h 2004-09-15 12:20:40.000000000 +0900 +++ linux-2.6.9-rc2-tbtc_tune/include/linux/sysctl.h 2004-09-28 15:12:33.000000000 +0900 @@ -167,6 +167,7 @@ enum VM_HUGETLB_GROUP=25, /* permitted hugetlb group */ VM_VFS_CACHE_PRESSURE=26, /* dcache/icache reclaim pressure */ VM_LEGACY_VA_LAYOUT=27, /* legacy/compatibility virtual address space layout */ + VM_SWAP_TOKEN_TIMEOUT=28 /* default time for token time out */ }; diff -uprN linux-2.6.9-rc2/kernel/sysctl.c linux-2.6.9-rc2-tbtc_tune/kernel/sysctl.c --- linux-2.6.9-rc2/kernel/sysctl.c 2004-09-15 12:20:41.000000000 +0900 +++ linux-2.6.9-rc2-tbtc_tune/kernel/sysctl.c 2004-09-28 15:12:33.000000000 +0900 @@ -800,6 +800,15 @@ static ctl_table vm_table[] = { .extra1 = &zero, }, #endif + { + .ctl_name = VM_SWAP_TOKEN_TIMEOUT, + .procname = "swap_token_timeout", + .data = &swap_token_default_timeout, + .maxlen = sizeof(swap_token_default_timeout), + .mode = 0644, + .proc_handler = &proc_dointvec, + .strategy = &sysctl_intvec, + }, { .ctl_name = 0 } }; diff -uprN linux-2.6.9-rc2/mm/thrash.c linux-2.6.9-rc2-tbtc_tune/mm/thrash.c --- linux-2.6.9-rc2/mm/thrash.c 2004-09-15 12:20:42.000000000 +0900 +++ linux-2.6.9-rc2-tbtc_tune/mm/thrash.c 2004-09-28 15:12:33.000000000 +0900 @@ -20,6 +20,8 @@ struct mm_struct * swap_token_mm = &init #define SWAP_TOKEN_CHECK_INTERVAL (HZ * 2) #define SWAP_TOKEN_TIMEOUT (HZ * 300) +unsigned long swap_token_default_timeout = SWAP_TOKEN_TIMEOUT; + /* * Take the token away if the process had no page faults @@ -75,10 +77,10 @@ void grab_swap_token(void) if ((reason = should_release_swap_token(mm))) { unsigned long eligible = jiffies; if (reason == SWAP_TOKEN_TIMED_OUT) { - eligible += SWAP_TOKEN_TIMEOUT; + eligible += swap_token_default_timeout; } mm->swap_token_time = eligible; - swap_token_timeout = jiffies + SWAP_TOKEN_TIMEOUT; + swap_token_timeout = jiffies + swap_token_default_timeout; swap_token_mm = current->mm; } spin_unlock(&swap_token_lock); - 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/