From: Andi Kleen <ak@linux.intel.com>
To: "Li, Aubrey" <aubrey.li@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Aubrey Li <aubrey.li@intel.com>,
mingo@redhat.com, peterz@infradead.org, hpa@zytor.com,
tim.c.chen@linux.intel.com, dave.hansen@intel.com,
arjan@linux.intel.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 1/3] x86/fpu: track AVX-512 usage of tasks
Date: Tue, 18 Dec 2018 13:38:26 -0800 [thread overview]
Message-ID: <20181218213826.GI25620@tassilo.jf.intel.com> (raw)
In-Reply-To: <b14a9c82-3336-0f13-1a27-fba929e6b4fb@linux.intel.com>
> I misunderstood, you mean 32bit kernel, not 32bit machine. Theoretically 32bit
> kernel can use AVX512, but not sure if anyone use it like this. get_jiffies_64()
> includes jiffies_lock ops so not good in context switch. So I want to use raw
> jiffies_64 here. jiffies is a good candidate but it has wraparound overflow issue.
> Other time source are expensive here.
>
> Should I limit the code only running on 64bit kernel?
Yes making it 64bit only should be fine.
Other alternative would be to use 32bit jiffies on 32bit. I assume
wrapping is not that big a problem here.
-Andi
next prev parent reply other threads:[~2018-12-18 21:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-18 4:22 [PATCH v6 1/3] x86/fpu: track AVX-512 usage of tasks Aubrey Li
2018-12-18 4:22 ` [PATCH v6 2/3] proc: add AVX-512 usage elapsed time to /proc/pid/status Aubrey Li
2018-12-18 4:22 ` [PATCH v6 3/3] Documentation/filesystems/proc.txt: add AVX512_elapsed_ms Aubrey Li
2018-12-18 14:14 ` [PATCH v6 1/3] x86/fpu: track AVX-512 usage of tasks Thomas Gleixner
2018-12-18 15:11 ` Li, Aubrey
2018-12-18 15:32 ` Thomas Gleixner
2018-12-18 16:28 ` Li, Aubrey
2018-12-18 21:38 ` Andi Kleen [this message]
2018-12-18 21:44 ` Dave Hansen
2018-12-18 22:05 ` Andi Kleen
2018-12-19 0:26 ` Li, Aubrey
2018-12-19 9:45 ` Thomas Gleixner
2018-12-18 17:14 ` Dave Hansen
2018-12-18 23:23 ` Li, Aubrey
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