From: Rusty Russell <rusty@rustcorp.com.au>
To: "David S. Miller" <davem@davemloft.net>
Cc: kiran@scalex86.org, akpm@osdl.org, linux-kernel@vger.kernel.org,
dipankar@in.ibm.com, bharata@in.ibm.com, shai@scalex86.org,
netdev@vger.kernel.org
Subject: Re: [patch 9/11] net: dst_entry.refcount, use, lastuse to use alloc_percpu
Date: Wed, 14 Sep 2005 17:21:02 +1000 [thread overview]
Message-ID: <1126682462.7896.103.camel@localhost.localdomain> (raw)
In-Reply-To: <20050913.162748.86496945.davem@davemloft.net>
On Tue, 2005-09-13 at 16:27 -0700, David S. Miller wrote:
> From: Ravikiran G Thirumalai <kiran@scalex86.org>
> Date: Tue, 13 Sep 2005 16:17:17 -0700
>
> > But even 1 Million dst cache entries would be 16+4 MB additional for
> > a 4 cpu box....is that too much?
>
> Absolutely.
>
> Per-cpu counters are great for things like single instance
> statistics et al. But once you start doing them per-object
> that's out of control bloat as far as I'm concerned.
This is why my original per-cpu allocator patch was damn slow, and
GFP_KERNEL only. I wasn't convinced that high-churn objects are a good
fit for spreading across cpus.
I thought that net devices and modules (which uses a primitive
hard-coded "bigref" currently) were a fair uses for bigrefs, though I'd
like to see some stats.
Cheers,
Rusty.
--
A bad analogy is like a leaky screwdriver -- Richard Braakman
prev parent reply other threads:[~2005-09-14 7:21 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20050913155112.GB3570@localhost.localdomain>
2005-09-13 16:10 ` [patch 7/11] net: Use bigrefs for net_device.refcount Ravikiran G Thirumalai
2005-09-13 16:26 ` Stephen Hemminger
2005-09-13 16:35 ` Ben Greear
2005-09-13 16:46 ` Stephen Hemminger
2005-09-13 20:26 ` David S. Miller
2005-09-13 22:16 ` Ravikiran G Thirumalai
2005-09-13 18:27 ` Eric Dumazet
2005-09-13 18:53 ` Ravikiran G Thirumalai
2005-09-13 16:12 ` [patch 8/11] net: dst_abstraction macros Ravikiran G Thirumalai
2005-09-13 16:17 ` [patch 9/11] net: dst_entry.refcount, use, lastuse to use alloc_percpu Ravikiran G Thirumalai
2005-09-13 20:24 ` David S. Miller
2005-09-13 22:07 ` Ravikiran G Thirumalai
2005-09-13 22:12 ` David S. Miller
2005-09-13 23:17 ` Ravikiran G Thirumalai
2005-09-13 23:27 ` David S. Miller
2005-09-14 7:21 ` Rusty Russell [this message]
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