From: Chuck Lever <chuck.lever@oracle.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Linux NFS Mailing List <linux-nfs@vger.kernel.org>, simo@redhat.com
Subject: Re: [PATCH RFC 04/10] SUNRPC: Add common byte-swapped RPC header constants
Date: Sat, 2 Feb 2019 17:49:35 -0500 [thread overview]
Message-ID: <52468C38-9E9C-49A7-B44B-2BE302A33145@oracle.com> (raw)
In-Reply-To: <20190202170258.GA14074@infradead.org>
> On Feb 2, 2019, at 12:02 PM, Christoph Hellwig <hch@infradead.org> wrote:
>
> On Fri, Feb 01, 2019 at 02:57:47PM -0500, Chuck Lever wrote:
>> Byte-swapping causes a CPU pipeline bubble on some processors. When
>> a decoder is comparing an on-the-wire value for equality, byte-
>> swapping can be avoided by comparing it directly to a pre-byte-
>> swapped constant value.
>
> Which ones?
I assume you mean on which processors have I observed CPU cycle
spikes around bswap instructions. I've seen this behavior only
on Intel processors of various families.
Would you prefer a different justification for this clean-up?
--
Chuck Lever
next prev parent reply other threads:[~2019-02-02 22:49 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-01 19:57 [PATCH RFC 00/10] SUNRPC GSS overhaul Chuck Lever
2019-02-01 19:57 ` [PATCH RFC 01/10] SUNRPC: Remove some dprintk() call sites from auth functions Chuck Lever
2019-02-04 19:04 ` J. Bruce Fields
2019-02-04 19:07 ` Chuck Lever
2019-02-01 19:57 ` [PATCH RFC 02/10] SUNRPC: Remove rpc_xprt::tsh_size Chuck Lever
2019-02-01 19:57 ` [PATCH RFC 03/10] SUNRPC: Add build option to disable support for insecure enctypes Chuck Lever
2019-02-01 19:57 ` [PATCH RFC 04/10] SUNRPC: Add common byte-swapped RPC header constants Chuck Lever
2019-02-02 2:30 ` Tom Talpey
2019-02-02 22:46 ` Chuck Lever
2019-02-03 15:00 ` Trond Myklebust
2019-02-03 16:49 ` Chuck Lever
2019-02-03 18:58 ` Trond Myklebust
2019-02-02 17:02 ` Christoph Hellwig
2019-02-02 22:49 ` Chuck Lever [this message]
2019-02-04 7:53 ` Christoph Hellwig
2019-02-04 14:16 ` Chuck Lever
2019-02-04 14:32 ` Christoph Hellwig
2019-02-04 14:56 ` Chuck Lever
2019-02-04 19:37 ` J. Bruce Fields
2019-02-05 1:57 ` Tom Talpey
2019-02-01 19:57 ` [PATCH RFC 05/10] SUNRPC: Use struct xdr_stream when constructing RPC Call header Chuck Lever
2019-02-01 19:57 ` [PATCH RFC 06/10] SUNRPC: Clean up rpc_verify_header() Chuck Lever
2019-02-01 19:58 ` [PATCH RFC 07/10] SUNRPC: Use struct xdr_stream when decoding RPC Reply header Chuck Lever
2019-02-01 19:58 ` [PATCH RFC 08/10] SUNRPC: Introduce trace points in rpc_auth_gss.ko Chuck Lever
2019-02-01 19:58 ` [PATCH RFC 09/10] SUNRPC: Remove xdr_buf_trim() Chuck Lever
2019-02-04 19:46 ` J. Bruce Fields
2019-02-04 19:49 ` Chuck Lever
2019-02-04 20:00 ` Bruce Fields
2019-02-04 20:07 ` Chuck Lever
2019-02-04 20:11 ` Bruce Fields
2019-02-01 19:58 ` [PATCH RFC 10/10] SUNRPC: Add SPDX IDs to some net/sunrpc/auth_gss/ files Chuck Lever
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