From: "H. Peter Anvin" <hpa@zytor.com>
To: Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
the arch/x86 maintainers <x86@kernel.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>,
Kees Cook <kees@kernel.org>, Xin Li <xin@zytor.com>,
"Ahmed S. Darwish" <darwi@linutronix.de>,
Sohil Mehta <sohil.mehta@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH v2 0/3] x86/fred: enable FRED by default
Date: Fri, 27 Mar 2026 18:20:32 -0700 [thread overview]
Message-ID: <80be63da-360b-41f5-a45f-81335f8af1c2@zytor.com> (raw)
In-Reply-To: <a7faee54-e13e-4403-be60-abbbc77978e0@app.fastmail.com>
On 2026-03-26 15:11, Andy Lutomirski wrote:
>
> Those performance increases while with fio / io_uring are ridiculous. I wonder whether anyone can looked at /proc/interrupts to try to figure out what's going on. I imagine we're bottlenecking on IO interrupts or something and FRED speeds that up by a factor of several, but this makes me wonder whether there's some tuning that should be done.
>
> Jens, for background, FRED ought to speed up page faults and interrupts (both IPI and device) by a considerable amount -- maybe a reduction of 20k or more cycles per interrupt. But Phoronix is showing up to a factor of 2 (!) actual performance increase using io_uring with a job count of 8. Now maybe 8 is too small, but I'm wondering whether the io_uring or IO part is missing some optimization that it ought to have.
>
Hi Andy! Long time no C!
Either way, I presume neither of you have any problems with the patchset itself?
-hpa
next prev parent reply other threads:[~2026-03-28 1:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-25 23:01 [PATCH v2 0/3] x86/fred: enable FRED by default H. Peter Anvin
2026-03-25 23:01 ` [PATCH v2 1/3] " H. Peter Anvin
2026-03-26 2:04 ` Sohil Mehta
2026-03-30 10:23 ` [tip: x86/fred] x86/fred: Enable " tip-bot2 for H. Peter Anvin
2026-03-25 23:01 ` [PATCH v2 2/3] x86/Kconfig: tighten up wording of the CONFIG_X86_FRED help text H. Peter Anvin
2026-03-26 16:26 ` Borislav Petkov
2026-03-25 23:01 ` [PATCH v2 3/3] x86/fred: Remove kernel log message when initializing exceptions H. Peter Anvin
2026-03-30 10:23 ` [tip: x86/fred] " tip-bot2 for Sohil Mehta
2026-03-26 22:11 ` [PATCH v2 0/3] x86/fred: enable FRED by default Andy Lutomirski
2026-03-26 22:26 ` Jens Axboe
2026-03-28 1:20 ` H. Peter Anvin [this message]
2026-04-03 15:29 ` Andy Lutomirski
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