On 30 September 2015 at 17:50, Aurelien Jarno <aurel...@aurel32.net> wrote: > On 2015-09-30 15:09, Richard Henderson wrote: >> We currently pre-compute an worst case code size for any TB, which >> works out to be 122kB. Since the average TB size is near 1kB, this >> wastes quite a lot of storage. > > The code generation buffer is currently computed as 1/4 of the guest > RAM in softmmu mode (so 32MB for the default 128MB of RAM) or 32MB in > user mode. 122kB is therefore less than 0.4% of waster memory, I am not > therefore sure we need to add so much code just for that.
I think the best argument for this patch is that it gets rid of the TCG_MAX_OP_SIZE guesswork about TCG op worst-cases. That sort of #define is generally arbitrary and liable to not get updated when new targets or backends invalidate previous assumptions. (Can we do anything to get rid of MAX_OP_PER_INSTR too?) thanks -- PMM