similar to: [PATCH v8 00/10] x86: macrofying inline asm for better compilation

On Mon, Jun 04, 2018 at 04:21:22AM -0700, Nadav Amit wrote: > This patch-set deals with an interesting yet stupid problem: kernel code > that does not get inlined despite its simplicity. There are several > causes for this behavior: "cold" attribute on __init, different function > optimization levels; conditional constant computations based on > __builtin_constant_p(); and

Hi people, this is an attempt to see whether gcc's inline asm heuristic when estimating inline asm statements' cost for better inlining can be improved. AFAIU, the problematic arises when one ends up using a lot of inline asm statements in the kernel but due to the inline asm cost estimation heuristic which counts lines, I think, for example like in this here macro:

* Nadav Amit <namit at vmware.com> wrote: > > I ran some limited number of benchmarks, and in general the performance > > impact is not very notable. You can still see >10 cycles shaved off some > > syscalls that manipulate page-tables (e.g., mprotect()), in which > > paravirt caused many functions not to be inlined. In addition this > > patch-set can

On Wed, Dec 19, 2018 at 5:26 AM Nadav Amit <namit at vmware.com> wrote: > > > On Dec 17, 2018, at 8:03 AM, Masahiro Yamada <yamada.masahiro at socionext.com> wrote: > > > > This series reverts the in-kernel workarounds for inlining issues. > > > > The commit description of 77b0bf55bc67 mentioned > > "We also hope that GCC will eventually get

On Tue, Jun 19, 2018 at 12:48:45PM -0700, Nadav Amit wrote: > Nadav Amit (9): > Makefile: Prepare for using macros for inline asm > x86: objtool: use asm macro for better compiler decisions > x86: refcount: prevent gcc distortions > x86: alternatives: macrofy locks for better inlining > x86: bug: prevent gcc distortions > x86: prevent inline distortion by paravirt

From: Nadav Amit > Sent: 17 May 2018 17:14 > This patch-set deals with an interesting yet stupid problem: kernel code > that does not get inlined despite its simplicity. There are several > causes for this behavior: "cold" attribute on __init, different function > optimization levels; conditional constant computations based on > __builtin_constant_p(); and finally large

* Nadav Amit <namit at vmware.com> wrote: > Ping. Masahiro Yamada noted that some Reviewed-by tags were not added - could you please double check past mails and add them and re-send against the latest kernel? Thanks, Ingo

On Sun, Dec 16, 2018 at 12:29 PM Nadav Amit <namit at vmware.com> wrote: > > > On Dec 15, 2018, at 6:50 PM, Masahiro Yamada <yamada.masahiro at socionext.com> wrote: > > > > Revert the following 9 commits: > > > > [1] 5bdcd510c2ac ("x86/jump-labels: Macrofy inline assembly code to > > work around GCC inlining bugs") > > >

* Masahiro Yamada <yamada.masahiro at socionext.com> wrote: > This series reverts the in-kernel workarounds for inlining issues. > > The commit description of 77b0bf55bc67 mentioned > "We also hope that GCC will eventually get fixed,..." > > Now, GCC provides a solution. > > https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html > explains the new

This series reverts the in-kernel workarounds for inlining issues. The commit description of 77b0bf55bc67 mentioned "We also hope that GCC will eventually get fixed,..." Now, GCC provides a solution. https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html explains the new "asm inline" syntax. The performance issue will be eventually solved. [About Code cleanups] I know Nadam

This series reverts the in-kernel workarounds for inlining issues. The commit description of 77b0bf55bc67 mentioned "We also hope that GCC will eventually get fixed,..." Now, GCC provides a solution. https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html explains the new "asm inline" syntax. The performance issue will be eventually solved. [About Code cleanups] I know Nadam

Revert the following 9 commits: [1] 5bdcd510c2ac ("x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs") This was partially reverted because it made good cleanups irrespective of the inlining issue; the error message is still unneeded, and the conversion to STATIC_BRANCH_{NOP,JUMP} should be kept. [2] d5a581d84ae6 ("x86/cpufeature:

On Mon, 2 Jul 2007, David A. Greene wrote: >>> - Changing the API >>> a) Template it to take two iterators. This causes code size bloat. > > This seems like the right solution to me. Unless llvm is running on > extremely limited memory embedded systems, the extra code space > shouldn't be an issue. Code size is always an issue. What specifically are you

On Monday 02 July 2007 16:26, Chris Lattner wrote: > On Sun, 1 Jul 2007, Nick Lewycky wrote: > > I've been running LLVM with _GLIBCXX_DEBUG (extra checks) turned on to > > see what would happen, and it's been a complete disaster. Well, that's a bit harsh, isn't it? It's finding bugs, just like it's supposed to. :) I believe I've started to run into

On 12/06/18 13:50, Nadav Amit wrote: > GCC considers the number of statements in inlined assembly blocks, > according to new-lines and semicolons, as an indication to the cost of > the block in time and space. This data is distorted by the kernel code, > which puts information in alternative sections. As a result, the > compiler may perform incorrect inlining and branch

No need to get into the submenu to disable all VIRTIO-related config entries. This makes it easier to disable all VIRTIO config options without entering the submenu. It will also enable one to see that en/dis-abled state from the outside menu. This is only intended to change menuconfig UI, not change the config dependencies. Signed-off-by: Vincent Legoll <vincent.legoll at gmail.com> ---

No need to get into the submenu to disable all VIRTIO-related config entries. This makes it easier to disable all VIRTIO config options without entering the submenu. It will also enable one to see that en/dis-abled state from the outside menu. This is only intended to change menuconfig UI, not change the config dependencies. Signed-off-by: Vincent Legoll <vincent.legoll at gmail.com> ---

Dear list, Whenever the flag "-Wstrict-prototypes" is set in gcc, compiling code that includes headers in lib/R/include generates often warnings (example with R-2.6.1: Rinternals.h:560: warning: function declaration isn't a prototype ). All such warnings I looked at were about functions with empty signatures declared as "bar foo();" rather than "bar

On Sun, 1 Jul 2007, Nick Lewycky wrote: > I've been running LLVM with _GLIBCXX_DEBUG (extra checks) turned on to > see what would happen, and it's been a complete disaster. > > The major problem is the use of this API: > > new CallInst(V, &Args[0], Args.size()); > > repeated throughout LLVM. When Args is empty, Args[0] is invalid, even > if the next

Hi Nadav, Thank you for the patch! Yet something to improve: [auto build test ERROR on linus/master] [also build test ERROR on v4.18-rc1 next-20180619] [cannot apply to tip/x86/core] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: