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From: Richard Weinberger <richard@nod.at>
To: anton ivanov <anton.ivanov@cambridgegreys.com>
Cc: linux-um <linux-um@lists.infradead.org>
Subject: Re: [PATCH] um: allow using glibc string functions instead of generics
Date: Tue, 10 Nov 2020 22:39:09 +0100 (CET)	[thread overview]
Message-ID: <1539736322.290788.1605044349917.JavaMail.zimbra@nod.at> (raw)
In-Reply-To: <de2e76d2-6adc-d9e9-7764-5d8ce22536bd@cambridgegreys.com>

----- Ursprüngliche Mail -----
> Von: "anton ivanov" <anton.ivanov@cambridgegreys.com>
> An: "richard" <richard@nod.at>
> CC: "linux-um" <linux-um@lists.infradead.org>
> Gesendet: Dienstag, 10. November 2020 22:33:48
> Betreff: Re: [PATCH] um: allow using glibc string functions instead of generics

> On 10/11/2020 21:29, Richard Weinberger wrote:
>> ----- Ursprüngliche Mail -----
>>> Von: "anton ivanov" <anton.ivanov@cambridgegreys.com>
>>>> On what workload did you see such a huge performance improvement?
>>> File IO ~ 1% or thereabouts, iperf - 2-4%.
>>>
>>>> The in-kernel variants of memcpy and such are already well optimized.
>>> UML has no string.h in asm which means it falls back to
>>> asm-generic/string.h which in turn pulls in the ones from lib/string.c
>>>
>>> These are not optimized.
>> Hmmm, I think it should use the highly optimized variants from arch/x86.
> 
> That is the other option - to bring in string32.h and string64.h from x86.

Yes, I thought we do so already. I fear we list this feature after some code
cleanup a long time ago.

I'm happy with either option.

Thanks,
//richard

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  reply	other threads:[~2020-11-10 21:39 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-10 16:30 [PATCH] um: allow using glibc string functions instead of generics anton.ivanov
2020-11-10 16:40 ` Johannes Berg
2020-11-10 16:54   ` Anton Ivanov
2020-11-10 20:13 ` Richard Weinberger
2020-11-10 20:56   ` Anton Ivanov
2020-11-10 21:29     ` Richard Weinberger
2020-11-10 21:33       ` Anton Ivanov
2020-11-10 21:39         ` Richard Weinberger [this message]
2020-11-11  7:13           ` Anton Ivanov
2020-11-11  8:26             ` Anton Ivanov
2020-11-11 15:14             ` Anton Ivanov
2020-11-11 15:59               ` Anton Ivanov
2020-11-11 18:09               ` Anton Ivanov
2020-11-11  9:49           ` Anton Ivanov

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