Re: [Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp

2015-03-30 Thread Laurent Desnogues
Hello, On Fri, Mar 27, 2015 at 10:09 PM, Emilio G. Cota wrote: > On Fri, Mar 27, 2015 at 09:55:03 +, Alex Bennée wrote: >> Have you been able to measure any performance improvement with these new >> structures? In theory, if aligned with cache lines, performance should >> improve but real num

Re: [Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp

2015-03-29 Thread Stefan Weil
Am 29.03.2015 um 23:52 schrieb Richard Henderson: No decrease in boot time is good. We /know/ we're saving memory, after all. Well, I would not mind a decrease in boot time, too. The more it decreases, the better. :-) To be honest: in my version I only used 1 bit bitfield entries for boolean v

Re: [Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp

2015-03-29 Thread Stefan Weil
Am 29.03.2015 um 23:52 schrieb Richard Henderson: On Mar 27, 2015 14:09, "Emilio G. Cota" wrote: On Fri, Mar 27, 2015 at 09:55:03 +, Alex Bennée wrote: Have you been able to measure any performance improvement with these new structures? In theory, if aligned with cache lines, performance s

Re: [Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp

2015-03-29 Thread Richard Henderson
On Mar 27, 2015 14:09, "Emilio G. Cota" wrote: > > On Fri, Mar 27, 2015 at 09:55:03 +, Alex Bennée wrote: > > Have you been able to measure any performance improvement with these new > > structures? In theory, if aligned with cache lines, performance should > > improve but real numbers woul

Re: [Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp

2015-03-27 Thread Emilio G. Cota
On Fri, Mar 27, 2015 at 09:55:03 +, Alex Bennée wrote: > Have you been able to measure any performance improvement with these new > structures? In theory, if aligned with cache lines, performance should > improve but real numbers would be nice. I haven't benchmarked anything, which makes me ve

Re: [Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp

2015-03-27 Thread Richard Henderson
On 03/25/2015 12:50 PM, Emilio G. Cota wrote: > This brings down the size of the struct from 56 to 32 bytes on 64-bit, > and to 16 bytes on 32-bit. > > The appended adds macros to prevent us from mistakenly overflowing > the bitfields when more elements are added to the corresponding > enums/macro

Re: [Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp

2015-03-27 Thread Alex Bennée
Emilio G. Cota writes: > This brings down the size of the struct from 56 to 32 bytes on 64-bit, > and to 16 bytes on 32-bit. Have you been able to measure any performance improvement with these new structures? In theory, if aligned with cache lines, performance should improve but real numbers w

[Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp

2015-03-25 Thread Emilio G. Cota
This brings down the size of the struct from 56 to 32 bytes on 64-bit, and to 16 bytes on 32-bit. The appended adds macros to prevent us from mistakenly overflowing the bitfields when more elements are added to the corresponding enums/macros. Note that reg/mem_reg need only 6 bits (for ia64) but