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Re: [patch][rfa] Don't Generate Code to Support Unused Write Stacks
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: Dave Brolley <brolley at redhat dot com>
- Cc: cgen at sources dot redhat dot com, sid at sources dot redhat dot com
- Date: 12 Jul 2006 19:20:06 -0400
- Subject: Re: [patch][rfa] Don't Generate Code to Support Unused Write Stacks
- References: <44B564FE.1030002@redhat.com>
brolley wrote:
> [...]
> When generating write stacks and the supporting code in order to
> suppor the (delay ...) rtl construct for SID, cgen currently generates
> a write stack for all registers and memory modes regardless of whether
> they are used or not. [...]
> For the internal port for which performance was an issue, this yielded
> an improvement of 17%. [...]
Sounds good. I'm surprised though that your change should cause such
a noticeable improvement. It may be that the sid-side code to handle
the write queue testing/iteration is rather deficient. (Try adding
some UNLIKELY markers to the CPU::writeback() function's while()
conditions.)
- FChE