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Re: Faster compilation speed
- From: Richard Earnshaw <rearnsha at arm dot com>
- To: Jeff Sturm <jsturm at one-point dot com>
- Cc: Richard dot Earnshaw at arm dot com, David Edelsohn <dje at watson dot ibm dot com>, Richard Henderson <rth at redhat dot com>, "David S. Miller" <davem at redhat dot com>, gcc at gcc dot gnu dot org
- Date: Tue, 20 Aug 2002 13:50:46 +0100
- Subject: Re: Faster compilation speed
- Organization: ARM Ltd.
- Reply-to: Richard dot Earnshaw at arm dot com
> > Do you have/can you get data for TLB misses?
>
> I had done that on alpha, but didn't initially report the figures. Would
> a comparison to 2.95 also be useful?
Certainly -- the numbers don't really mean anything unless we have
something to compare them against. Remember, gcc-2.95 bootstrap times
were about half those that we have now (*after* taking into account new
languages and libraries etc).
R.
>
> gcc version 3.3 20020802 (experimental)
>
> ---------------------------------------------------------------------------
> cc1 -O2 reload.i
>
> issues/cycles = 0.51 issues/dcache_miss = 26.93 issues/dtb_miss = 1214.36
So if I understand these figures correctly, then
dcache_miss/dtb_miss ~= 45
That is, one in 45 dcache fetches also requires a tlb walk. How many dtb
entries does an Alpha have?
>
> ---------------------------------------------------------------------------
> cc1 reload.i
>
> issues/cycles = 0.52 issues/dcache_miss = 31.29 issues/dtb_miss = 1854.16
>
giving
dcache_miss/dtb_miss ~= 60