From: Dave Hansen <dave.hansen@linux.intel.com> To: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, "Andrew Lutomirski" <luto@kernel.org>, "Kees Cook" <keescook@google.com>, "Hugh Dickins" <hughd@google.com>, "Jürgen Groß" <jgross@suse.com>, "the arch/x86 maintainers" <x86@kernel.org> Subject: Re: [PATCH 0/3] Use global pages with PTI Date: Thu, 15 Feb 2018 15:55:45 -0800 [thread overview] Message-ID: <91298252-6cef-d4ee-fa77-eb4008eb5f53@linux.intel.com> (raw) In-Reply-To: <CA+55aFy8k_zSJ_ASyzkA9C-jLV4mZsHpv1sOxJ9qpvfS_P6eMg@mail.gmail.com> On 02/15/2018 09:47 AM, Linus Torvalds wrote: > On Thu, Feb 15, 2018 at 5:20 AM, Dave Hansen > <dave.hansen@linux.intel.com> wrote: >> During the switch over to PTI, we seem to have lost our ability to have >> GLOBAL mappings. ... > Did you perhaps re-run any benchmark numbers just to verify? Because > it's always good to back up patches that should improve performance > with actual numbers.. Same test as last time except I'm using all 4 cores on a Skylake desktop instead of just 1. The test is this: > https://github.com/antonblanchard/will-it-scale/blob/master/tests/lseek1.c With PCIDs, lseek()s/second go up around 2% to 3% with the these patches enabling the global bit (it's noisy). I measured it at 3% before, so definitely the same ballpark. That was also before all of Andy's trampoline stuff and the syscall fast path removal.
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From: Dave Hansen <dave.hansen@linux.intel.com> To: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, "Andrew Lutomirski" <luto@kernel.org>, "Kees Cook" <keescook@google.com>, "Hugh Dickins" <hughd@google.com>, "Jürgen Groß" <jgross@suse.com>, "the arch/x86 maintainers" <x86@kernel.org> Subject: Re: [PATCH 0/3] Use global pages with PTI Date: Thu, 15 Feb 2018 15:55:45 -0800 [thread overview] Message-ID: <91298252-6cef-d4ee-fa77-eb4008eb5f53@linux.intel.com> (raw) In-Reply-To: <CA+55aFy8k_zSJ_ASyzkA9C-jLV4mZsHpv1sOxJ9qpvfS_P6eMg@mail.gmail.com> On 02/15/2018 09:47 AM, Linus Torvalds wrote: > On Thu, Feb 15, 2018 at 5:20 AM, Dave Hansen > <dave.hansen@linux.intel.com> wrote: >> During the switch over to PTI, we seem to have lost our ability to have >> GLOBAL mappings. ... > Did you perhaps re-run any benchmark numbers just to verify? Because > it's always good to back up patches that should improve performance > with actual numbers.. Same test as last time except I'm using all 4 cores on a Skylake desktop instead of just 1. The test is this: > https://github.com/antonblanchard/will-it-scale/blob/master/tests/lseek1.c With PCIDs, lseek()s/second go up around 2% to 3% with the these patches enabling the global bit (it's noisy). I measured it at 3% before, so definitely the same ballpark. That was also before all of Andy's trampoline stuff and the syscall fast path removal. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2018-02-15 23:55 UTC|newest] Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-02-15 13:20 [PATCH 0/3] Use global pages with PTI Dave Hansen 2018-02-15 13:20 ` Dave Hansen 2018-02-15 13:20 ` [PATCH 1/3] x86/mm: factor out conditional pageattr PTE bit setting code Dave Hansen 2018-02-15 13:20 ` Dave Hansen 2018-02-15 13:20 ` [PATCH 2/3] x86/mm: introduce __PAGE_KERNEL_GLOBAL Dave Hansen 2018-02-15 13:20 ` Dave Hansen 2018-02-16 17:47 ` Nadav Amit 2018-02-16 17:47 ` Nadav Amit 2018-02-16 18:03 ` Dave Hansen 2018-02-16 18:03 ` Dave Hansen 2018-02-16 18:25 ` Nadav Amit 2018-02-16 18:25 ` Nadav Amit 2018-02-16 19:06 ` Dave Hansen 2018-02-16 19:06 ` Dave Hansen 2018-02-16 19:54 ` Nadav Amit 2018-02-16 19:54 ` Nadav Amit 2018-02-16 20:00 ` Dave Hansen 2018-02-16 20:00 ` Dave Hansen 2018-02-16 23:19 ` Dave Hansen 2018-02-16 23:19 ` Dave Hansen 2018-02-15 13:20 ` [PATCH 3/3] x86/pti: enable global pages for shared areas Dave Hansen 2018-02-15 13:20 ` Dave Hansen 2018-02-15 17:47 ` [PATCH 0/3] Use global pages with PTI Linus Torvalds 2018-02-15 17:47 ` Linus Torvalds 2018-02-15 18:13 ` Dave Hansen 2018-02-15 18:13 ` Dave Hansen 2018-02-15 23:55 ` Dave Hansen [this message] 2018-02-15 23:55 ` Dave Hansen -- strict thread matches above, loose matches on Subject: below -- 2018-02-13 23:19 Dave Hansen
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