From: Volker Lendecke <Volker.Lendecke@SerNet.DE>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, Steven French <sfrench@us.ibm.com>,
Jens Axboe <jens.axboe@oracle.com>,
netdev@vger.kernel.org
Subject: Re: maximum buffer size for splice(2) tcp->pipe?
Date: Wed, 14 Jan 2009 11:03:30 +0100 [thread overview]
Message-ID: <E1LN2Vu-00DluN-6Z@intern.SerNet.DE> (raw)
In-Reply-To: <496DACBE.3030701@cosmosbay.com>
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On Wed, Jan 14, 2009 at 10:13:34AM +0100, Eric Dumazet wrote:
> for (;;) {
> struct pollfd pfd;
> pfd.fd = socket;
> pfd.events = POLLIN;
> if (poll(&pfd, 1, -1) != 1)
> continue;
> res = splice(socket, NULL, pipefds[1], NULL, 65536, SPLICE_F_MOVE|SPLICE_F_NONBLOCK);
> if (res > 0)
> nwritten = splice(pipefds[0], NULL, file_fd, NULL, res, SPLICE_F_MOVE|SPLICE_F_MORE);
> }
Doesn't this reduce performance again? I thought the whole
point of splice() was to increase performance by avoiding
memory copies. If I have to do a poll syscall for each call
to splice, doesn't the context switch eat that performance
advantage again?
Or was splice designed only for multi-threaded applications
(which at least Samba is not)?
Volker
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next prev parent reply other threads:[~2009-01-14 9:58 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-08 10:13 Volker Lendecke
2009-01-13 20:37 ` Andrew Morton
2009-01-13 23:15 ` Eric Dumazet
2009-01-13 23:38 ` Eric Dumazet
2009-01-15 4:58 ` David Miller
2009-01-15 11:47 ` Eric Dumazet
2009-01-14 7:40 ` Volker Lendecke
2009-01-14 9:13 ` Eric Dumazet
2009-01-14 10:03 ` Volker Lendecke [this message]
2009-01-14 10:17 ` Eric Dumazet
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