Messages in this thread | | | Date | Tue, 13 Nov 2007 22:37:26 -0800 (PST) | Subject | Re: 2.6.24-rc2: Network commit causes SLUB performance regression with tbench | From | David Miller <> |
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From: Nick Piggin <nickpiggin@yahoo.com.au> Date: Wed, 14 Nov 2007 05:14:27 +1100
> On Wednesday 14 November 2007 17:12, David Miller wrote: > > Is your test system using HIGHMEM? > > > > That's one thing the page vector in the sk_buff can do a lot, > > kmaps. > > No, it's an x86-64, so no highmem.
Ok.
> What's also interesting is that SLAB apparently doesn't have this > condition. The first thing that sprung to mind is that SLAB caches > order > 0 allocations, while SLUB does not. However if anything, > that should actually favour the SLUB numbers if network is avoiding > order > 0 allocations. > > I'm doing some oprofile runs now to see if I can get any more info.
Here are some other things you can play around with:
1) Monitor the values of skb->len and skb->data_len for packets going over loopback.
2) Try removing NETIF_F_SG in drivers/net/loopback.c's dev->feastures setting. - 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/
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