Dipankar Sarma wrote:
> In article <firstname.lastname@example.org> David S. Miller wrote:
> > From: Rik van Riel <email@example.com>
> > Date: Tue, 25 Sep 2001 17:24:21 -0300 (BRST)
> > Or were you measuring loads which are mostly read-only ?
> > When Kanoj Sarcar was back at SGI testing 32 processor Origin
> > MIPS systems, pagecache_lock was at the top.
> John Hawkes from SGI had published some AIM7 numbers that showed
> pagecache_lock to be a bottleneck above 4 processors. At 32 processors,
> half the CPU cycles were spent on waiting for pagecache_lock. The
> thread is at -
That's NUMA hardware. The per-hashqueue locking change made
a big improvement on that hardware. But when it was used on
Intel hardware it made no measurable difference at all.
Sorry, but the patch adds compexity and unless a significant
throughput benefit can be demonstrated on less exotic hardware,
why use it?
Here are kumon's test results from March, with and without
the hashed lock patch:
-------- Original Message --------
Subject: Re: [Fwd: Re: [Lse-tech] AIM7 scaling, pagecache_lock, multiqueue scheduler]
Date: Thu, 15 Mar 2001 18:03:55 +0900
To: Andrew Morton <firstname.lastname@example.org>
CC: email@example.com, firstname.lastname@example.org,John Hawkes <email@example.com>,firstname.lastname@example.org
OK, the followings are a result of our brief measurement with WebBench
(mindcraft type) of 2.4.2 and 2.4.2+pcl .
Workload: WebBench 3.0 (static get)
Machine: Profusion 8way 550MHz/1MB cache 1GB mem.
Server: Apache 1.3.9-8 (w/ SINGLE_LISTEN_UNSERIALIZED_ACCEPT)
obtained from RedHat.
Clients: 32 clients each has 2 requesting threads.
The following number is Request per sec.
242 242+pcl ratio
1SMP 1,603 1,584 0.99
2(1+1)SMP 2,443 2,437 1.00
4(1+3)SMP 4,420 4,426 1.00
8(4+4)SMP 5,381 5,400 1.00
#No idle time observed in the 1 to 4 SMP runs.
#Only 8 SMP cases shows cpu-idle time, but it is about 2.1-2.8% of the
#total CPU time.
Note: The load of two buses of Profusion system isn't balance, because
the number of CPUs on each bus is unbalance.
From the above brief test, (+pcl) patch doens't show the measurable
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This archive was generated by hypermail 2b29 : Sun Sep 30 2001 - 21:00:40 EST