From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
linux-arch@vger.kernel.org, David Miller <davem@davemloft.net>,
Russell King <rmk@arm.linux.org.uk>
Subject: Re: Software prefetching considered harmful
Date: Fri, 20 May 2011 19:13:28 +1000 [thread overview]
Message-ID: <1305882808.7481.163.camel@pasglop> (raw)
In-Reply-To: <20110520083442.GB22802@elte.hu>
> Yeah, over the past 10 years we have been suffering from an increasing level of
> blindness in the area of x86 performance analysis. Our old tools gradually
> deteriorated, the hardware got smarter and more parallel and it was harder and
> harder to see what happens. The 32-bit/64-bit split did not help us stay
> focused either. I think i warned about this 4-5 years ago at a KS.
>
> This has improved meanwhile, we now have better tools (*wink* :) and have a
> good performance monitoring model (*wink* :) and people are again looking at
> the fine details and i think we now have a good chance to speed up the kernel
> again and keep it fast - and not just on PowerPC which has its envied Olympus
> of performance gods! :-)
Hehe, right. I agree completely.
> Watching out for performance is a fundamentally critical mass thing: for a long
> time it seems a Sisyphean task with little progress, then it just happens very
> quickly.
I used to pay a lot more attention to performance myself than I do
nowadays, and that is definitely not a good thing. Mostly blame being
swamped with other things but still something I need to remedy in the
near future.
Cheers,
Ben.
prev parent reply other threads:[~2011-05-20 9:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-19 17:12 Software prefetching considered harmful Linus Torvalds
2011-05-19 19:05 ` Linus Torvalds
2011-05-19 19:28 ` Ingo Molnar
2011-05-21 3:37 ` Michael Cree
2011-05-21 4:18 ` Benjamin Herrenschmidt
2011-05-21 10:42 ` Ingo Molnar
2011-05-19 19:32 ` David Miller
2011-05-19 19:38 ` Linus Torvalds
2011-05-19 19:47 ` David Miller
2011-05-19 23:34 ` Ingo Molnar
2011-05-20 16:01 ` Catalin Marinas
2011-05-20 1:42 ` Benjamin Herrenschmidt
2011-05-20 8:34 ` Ingo Molnar
2011-05-20 9:13 ` Benjamin Herrenschmidt [this message]
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