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From: Mitchell Erblich <erblichs@earthlink.net>
To: linux-kernel@vger.kernel.org
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Subject: Suggested code change : Simple : Scale pdflush threads from desktop to server
Date: Fri, 10 Jul 2009 18:25:26 -0700
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1382
Lines: 46

Group,

		pdflush threads clean dirty pages

	  Under the past simple assumption that a greater number of
	  page daemon threads will have the TENDENCY to clean
	  the pages faster.

	Another assumption is that a server will have at least 2x / 4x the
	number of drives and memory, so allocating more pdflush() threads
	makes sense.

	Relying on a recent change, code base on whether the system is
	a desktop or a server, scale the number of pdthreads() which would
	result in the below code change.

	The suggestion is to double the MIN number of threads and set the
	MAX number to 4x.

	./mm/pdflush.c
	/* Scale for a server */
	#define MIN_PDFLUSH_THREADS 	4		/* 2x desktop value */
	#define MAX_PDFLUSH_THREADS 	32		/* 4x desktop value */


	/*
	 * secondary suggestion is to add a DEBUG type /var/log/system  
messages that
	 * will rate limit independent of desktop or server.
          */

	else if (nr_pdflush_threads == MAX_PDFLUSH_THREADS) {
		   /* optional PDFLUSH msg */
		   if (printk_ratelimit() {
	 		                            printk(KERN_INFO "MAX_PDFLUSH_THREADS  
Limited\n");
                    }
          }
	

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