From: Andi Kleen <ak@suse.de>
To: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: David Miller <davem@davemloft.net>,
Ulrich Drepper <drepper@redhat.com>,
Andrew Morton <akpm@osdl.org>, netdev <netdev@vger.kernel.org>,
Zach Brown <zach.brown@oracle.com>,
Christoph Hellwig <hch@infradead.org>,
Chase Venters <chase.venters@clientec.com>,
Johann Borck <johann.borck@densedata.com>,
linux-kernel@vger.kernel.org, Jeff Garzik <jeff@garzik.org>,
Jamal Hadi Salim <hadi@cyberus.ca>, Ingo Molnar <mingo@elte.hu>,
linux-fsdevel@vger.kernel.org
Subject: Re: [take36 10/10] kevent: Kevent based generic AIO.
Date: 12 Feb 2007 14:08:10 +0100 [thread overview]
Message-ID: <p733b5bh6bp.fsf@bingen.suse.de> (raw)
In-Reply-To: <1171279650540@2ka.mipt.ru>
Evgeniy Polyakov <johnpol@2ka.mipt.ru> writes:
>
> aio_sendfile_path() is essentially aio_sendfile(), except that it takes
> source filename as parameter, has a pointer to private header
> and its size (which allows to send header and file's content in one syscall
> instead of three (open, send, sendfile) and returns opened file descriptor.
Are you sure this is a useful optimization? Do you have numbers vs open+aio_sendfile+close?
Compared to the cost of sending a complete file three system calls should be quite in the noise.
And Linux system calls are not that expensive (few hundred cycles normally)
Adding such compound system calls would be a worrying precedent because
I'm sure others would want them then for their favourite system call combo
too. If they were really useful it might make more sense to have a batch()
system call that works for arbitary calls, but I'm not convinced yet
it's even needed. It would be certainly ugly.
-Andi
next prev parent reply other threads:[~2007-02-12 13:08 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <11712796473213@2ka.mipt.ru>
2007-02-12 11:27 ` [take36 3/10] kevent: poll/select() notifications Evgeniy Polyakov
2007-02-12 11:27 ` [take36 4/10] kevent: Socket notifications Evgeniy Polyakov
2007-02-12 11:27 ` [take36 5/10] kevent: Timer notifications Evgeniy Polyakov
2007-02-12 11:27 ` [take36 6/10] kevent: Pipe notifications Evgeniy Polyakov
2007-02-12 11:27 ` [take36 7/10] kevent: Signal notifications Evgeniy Polyakov
2007-02-12 11:27 ` [take36 8/10] kevent: Kevent posix timer notifications Evgeniy Polyakov
2007-02-12 11:27 ` [take36 9/10] kevent: Private userspace notifications Evgeniy Polyakov
2007-02-12 11:27 ` [take36 10/10] kevent: Kevent based generic AIO Evgeniy Polyakov
2007-02-12 13:08 ` Andi Kleen [this message]
2007-02-12 12:19 ` Evgeniy Polyakov
2007-02-12 13:12 ` Alan
2007-02-12 13:24 ` Evgeniy Polyakov
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