linux-kernel - Re: [GIT PULL] Clang feature updates for v5.14-rc1

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YN9ho7yDFStVw8g3@hirez.programming.kicks-ass.net>
Date:   Fri, 2 Jul 2021 20:57:39 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     Bill Wendling <morbo@...gle.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Kees Cook <keescook@...omium.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Bill Wendling <wcw@...gle.com>,
        Catalin Marinas <catalin.marinas@....com>,
        clang-built-linux <clang-built-linux@...glegroups.com>,
        Fangrui Song <maskray@...gle.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Jarmo Tiitto <jarmo.tiitto@...il.com>,
        Lukas Bulwahn <lukas.bulwahn@...il.com>,
        Mark Rutland <mark.rutland@....com>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Miguel Ojeda <ojeda@...nel.org>,
        Nathan Chancellor <nathan@...nel.org>,
        Peter Oberparleiter <oberpar@...ux.ibm.com>,
        Sami Tolvanen <samitolvanen@...gle.com>,
        Will Deacon <will@...nel.org>
Subject: Re: [GIT PULL] Clang feature updates for v5.14-rc1

On Fri, Jul 02, 2021 at 10:26:40AM -0700, Nick Desaulniers wrote:
> On Fri, Jul 2, 2021 at 5:57 AM Peter Zijlstra <peterz@...radead.org> wrote:

> > I've asked this before; *what* is missing from LBR samples that's
> > reponsible for the performance gap?
> 
> Are we able to collect LBR samples from __init code?  I can imagine
> trying to launch perf from init/pid 1, but I suspect at that point
> it's way too late.
> 
> Increasingly, boot times of hosts (and virtualized guests) are
> becoming important to us, both in the datacenters and on mobile.

For a guest, possibly, I've no idea how any of that virt crud works.