Re: [v2,12/18] kbuild: add support for clang LTO

2017-11-29 Thread Sami Tolvanen
On Tue, Nov 21, 2017 at 11:01:52AM +1000, Nicholas Piggin wrote: > I just wonder are you doing this because there is some worthwhile > performance gain? Or to enable more testing and development of LTO? > Any clues for why a user would want to enable it. I'm primarily interested in CFI, which

Re: [v2,12/18] kbuild: add support for clang LTO

2017-11-29 Thread Sami Tolvanen
On Tue, Nov 21, 2017 at 11:01:52AM +1000, Nicholas Piggin wrote: > I just wonder are you doing this because there is some worthwhile > performance gain? Or to enable more testing and development of LTO? > Any clues for why a user would want to enable it. I'm primarily interested in CFI, which

Re: [v2,12/18] kbuild: add support for clang LTO

2017-11-20 Thread Nicholas Piggin
On Mon, 20 Nov 2017 12:21:52 -0800 Sami Tolvanen wrote: > On Sat, Nov 18, 2017 at 01:21:39PM +1000, Nicholas Piggin wrote: > > Do you have any kind of numbers for this, out of curiosity? Binary > > size, performance, build time? > > I don't have performance numbers to

Re: [v2,12/18] kbuild: add support for clang LTO

2017-11-20 Thread Nicholas Piggin
On Mon, 20 Nov 2017 12:21:52 -0800 Sami Tolvanen wrote: > On Sat, Nov 18, 2017 at 01:21:39PM +1000, Nicholas Piggin wrote: > > Do you have any kind of numbers for this, out of curiosity? Binary > > size, performance, build time? > > I don't have performance numbers to share. Are there any

Re: [v2,12/18] kbuild: add support for clang LTO

2017-11-20 Thread Sami Tolvanen
On Sat, Nov 18, 2017 at 01:21:39PM +1000, Nicholas Piggin wrote: > Do you have any kind of numbers for this, out of curiosity? Binary > size, performance, build time? I don't have performance numbers to share. Are there any specific benchmarks you'd be interested in seeing? Build time typically

Re: [v2,12/18] kbuild: add support for clang LTO

2017-11-20 Thread Sami Tolvanen
On Sat, Nov 18, 2017 at 01:21:39PM +1000, Nicholas Piggin wrote: > Do you have any kind of numbers for this, out of curiosity? Binary > size, performance, build time? I don't have performance numbers to share. Are there any specific benchmarks you'd be interested in seeing? Build time typically

Re: [v2,12/18] kbuild: add support for clang LTO

2017-11-17 Thread Nicholas Piggin
On Wed, 15 Nov 2017 13:34:22 -0800 Sami Tolvanen wrote: > This change adds the configuration option CONFIG_LTO_CLANG, and > build system support for clang's Link Time Optimization (LTO). In > preparation for LTO support for other compilers, potentially common > parts of

Re: [v2,12/18] kbuild: add support for clang LTO

2017-11-17 Thread Nicholas Piggin
On Wed, 15 Nov 2017 13:34:22 -0800 Sami Tolvanen wrote: > This change adds the configuration option CONFIG_LTO_CLANG, and > build system support for clang's Link Time Optimization (LTO). In > preparation for LTO support for other compilers, potentially common > parts of the changes are gated