From: Minchan Kim <minchan.kim@gmail.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
Linux Kernel List <linux-kernel@vger.kernel.org>,
Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Wu Fengguang <fengguang.wu@intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Dave Chinner <david@fromorbit.com>,
Chris Mason <chris.mason@oracle.com>,
Christoph Hellwig <hch@lst.de>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/9] Reduce latencies and improve overall reclaim efficiency v1
Date: Tue, 14 Sep 2010 08:10:21 +0900 [thread overview]
Message-ID: <AANLkTinq6v3-NKjszYVOR3qxr-UVNoGw0uQjBGcoifVs@mail.gmail.com> (raw)
In-Reply-To: <1283770053-18833-1-git-send-email-mel@csn.ul.ie>
On Mon, Sep 6, 2010 at 7:47 PM, Mel Gorman <mel@csn.ul.ie> wrote:
<snip>
>
> These are just the raw figures taken from /proc/vmstat. It's a rough measure
> of reclaim activity. Note that allocstall counts are higher because we
> are entering direct reclaim more often as a result of not sleeping in
> congestion. In itself, it's not necessarily a bad thing. It's easier to
> get a view of what happened from the vmscan tracepoint report.
>
> FTrace Reclaim Statistics: vmscan
> micro-traceonly-v1r5-micromicro-nocongest-v1r5-micromicro-lowlumpy-v1r5-micromicro-nodirect-v1r5-micro
> traceonly-v1r5 nocongest-v1r5 lowlumpy-v1r5 nodirect-v1r5
> Direct reclaims 152 941 967 729
> Direct reclaim pages scanned 507377 1404350 1332420 1450213
> Direct reclaim pages reclaimed 10968 72042 77186 41097
> Direct reclaim write file async I/O 0 0 0 0
> Direct reclaim write anon async I/O 0 0 0 0
> Direct reclaim write file sync I/O 0 0 0 0
> Direct reclaim write anon sync I/O 0 0 0 0
> Wake kswapd requests 127195 241025 254825 188846
> Kswapd wakeups 6 1 1 1
> Kswapd pages scanned 4210101 3345122 3427915 3306356
> Kswapd pages reclaimed 2228073 2165721 2143876 2194611
> Kswapd reclaim write file async I/O 0 0 0 0
> Kswapd reclaim write anon async I/O 0 0 0 0
> Kswapd reclaim write file sync I/O 0 0 0 0
> Kswapd reclaim write anon sync I/O 0 0 0 0
> Time stalled direct reclaim (seconds) 7.60 3.03 3.24 3.43
> Time kswapd awake (seconds) 12.46 9.46 9.56 9.40
>
> Total pages scanned 4717478 4749472 4760335 4756569
> Total pages reclaimed 2239041 2237763 2221062 2235708
> %age total pages scanned/reclaimed 47.46% 47.12% 46.66% 47.00%
> %age total pages scanned/written 0.00% 0.00% 0.00% 0.00%
> %age file pages scanned/written 0.00% 0.00% 0.00% 0.00%
> Percentage Time Spent Direct Reclaim 43.80% 21.38% 22.34% 23.46%
> Percentage Time kswapd Awake 79.92% 79.56% 79.20% 80.48%
There is a nitpick about stalled reclaim time.
For example, In direct reclaim
===
trace_mm_vmscan_direct_reclaim_begin(order,
sc.may_writepage,
gfp_mask);
nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
trace_mm_vmscan_direct_reclaim_end(nr_reclaimed);
===
In this case, Isn't this time accumulated value?
My point is following as.
Process A Process B
direct reclaim begin
do_try_to_free_pages
cond_resched
direct reclaim begin
do_try_to_free_pages
direct reclaim end
direct reclaim end
So A's result includes B's time so total stall time would be bigger than real.
--
Kind regards,
Minchan Kim
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prev parent reply other threads:[~2010-09-13 23:10 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-06 10:47 Mel Gorman
2010-09-06 10:47 ` [PATCH 01/10] tracing, vmscan: Add trace events for LRU list shrinking Mel Gorman
2010-09-06 10:47 ` [PATCH 02/10] writeback: Account for time spent congestion_waited Mel Gorman
2010-09-06 10:47 ` [PATCH 03/10] writeback: Do not congestion sleep if there are no congested BDIs or significant writeback Mel Gorman
2010-09-07 15:25 ` Minchan Kim
2010-09-08 11:04 ` Mel Gorman
2010-09-08 14:52 ` Minchan Kim
2010-09-09 8:54 ` Mel Gorman
2010-09-12 15:37 ` Minchan Kim
2010-09-13 8:55 ` Mel Gorman
2010-09-13 9:48 ` Minchan Kim
2010-09-13 10:07 ` Mel Gorman
2010-09-13 10:20 ` Minchan Kim
2010-09-13 10:30 ` Mel Gorman
2010-09-08 21:23 ` Andrew Morton
2010-09-09 10:43 ` Mel Gorman
2010-09-09 3:02 ` KAMEZAWA Hiroyuki
2010-09-09 8:58 ` Mel Gorman
2010-09-06 10:47 ` [PATCH 04/10] vmscan: Synchronous lumpy reclaim should not call congestion_wait() Mel Gorman
2010-09-07 15:26 ` Minchan Kim
2010-09-08 6:15 ` Johannes Weiner
2010-09-08 11:25 ` Wu Fengguang
2010-09-09 3:03 ` KAMEZAWA Hiroyuki
2010-09-06 10:47 ` [PATCH 05/10] vmscan: Synchrounous lumpy reclaim use lock_page() instead trylock_page() Mel Gorman
2010-09-07 15:28 ` Minchan Kim
2010-09-08 6:16 ` Johannes Weiner
2010-09-08 11:28 ` Wu Fengguang
2010-09-09 3:04 ` KAMEZAWA Hiroyuki
2010-09-09 3:15 ` KAMEZAWA Hiroyuki
2010-09-09 3:25 ` Wu Fengguang
2010-09-09 4:13 ` KOSAKI Motohiro
2010-09-09 9:22 ` Mel Gorman
2010-09-10 10:25 ` KOSAKI Motohiro
2010-09-10 10:33 ` KOSAKI Motohiro
2010-09-13 9:14 ` Mel Gorman
2010-09-14 10:14 ` KOSAKI Motohiro
2010-09-06 10:47 ` [PATCH 06/10] vmscan: Narrow the scenarios lumpy reclaim uses synchrounous reclaim Mel Gorman
2010-09-09 3:14 ` KAMEZAWA Hiroyuki
2010-09-06 10:47 ` [PATCH 07/10] vmscan: Remove dead code in shrink_inactive_list() Mel Gorman
2010-09-07 15:33 ` Minchan Kim
2010-09-06 10:47 ` [PATCH 08/10] vmscan: isolated_lru_pages() stop neighbour search if neighbour cannot be isolated Mel Gorman
2010-09-07 15:37 ` Minchan Kim
2010-09-08 11:12 ` Mel Gorman
2010-09-08 14:58 ` Minchan Kim
2010-09-08 11:37 ` Wu Fengguang
2010-09-08 12:50 ` Mel Gorman
2010-09-08 13:14 ` Wu Fengguang
2010-09-08 13:27 ` Mel Gorman
2010-09-09 3:17 ` KAMEZAWA Hiroyuki
2010-09-06 10:47 ` [PATCH 09/10] vmscan: Do not writeback filesystem pages in direct reclaim Mel Gorman
2010-09-13 13:31 ` Wu Fengguang
2010-09-13 13:55 ` Mel Gorman
2010-09-13 14:33 ` Wu Fengguang
2010-10-28 21:50 ` Christoph Hellwig
2010-10-29 10:26 ` Mel Gorman
2010-09-06 10:47 ` [PATCH 10/10] vmscan: Kick flusher threads to clean pages when reclaim is encountering dirty pages Mel Gorman
2010-09-09 3:22 ` KAMEZAWA Hiroyuki
2010-09-09 9:32 ` Mel Gorman
2010-09-13 0:53 ` KAMEZAWA Hiroyuki
2010-09-13 13:48 ` Wu Fengguang
2010-09-13 14:10 ` Mel Gorman
2010-09-13 14:41 ` Wu Fengguang
2010-09-06 10:49 ` [PATCH 0/9] Reduce latencies and improve overall reclaim efficiency v1 Mel Gorman
2010-09-08 3:14 ` KOSAKI Motohiro
2010-09-08 8:38 ` Mel Gorman
2010-09-13 23:10 ` Minchan Kim [this message]
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