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Date: Mon, 26 Jul 2010 15:41:25 +0800 From: Changli Gao <xiaosuo@...il.com> To: Ofer Heifetz <oferh@...vell.com> Cc: Eric Dumazet <eric.dumazet@...il.com>, Jens Axboe <axboe@...nel.dk>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>, Nick Piggin <npiggin@...e.de> Subject: Re: Splice status On Sun, Jul 25, 2010 at 10:47 PM, Ofer Heifetz <oferh@...vell.com> wrote: > Hi Eric, > > Still trying to get better performance with splice, I noticed that when using splice there are twice the file size memcpy (placed a counter in memcpy), I verified it via samba file transfer and splice-fromnet/out. > > I also used the splice-fromnet/out and using ftrace I did notice that data is copied twice using these routines: skb_splice_bits, pipe_to_file. > > I thought that the main goal of splice is to refrain from one copy when moving data from network to file descriptor. > > If there are the same number of memcpy and context switches and in samba copy additional vfs overhead it makes sense that splice deteriates the samba overall write performance. > The support for SPLICE_F_MOVE is removed by Nick in commit http://git.kernel.org/?p=linux/kernel/git/next/linux-next.git;a=commitdiff;h=485ddb4b9741bafb70b22e5c1f9b4f37dc3e85bd . Nick, can we add it back now? -- Regards, Changli Gao(xiaosuo@...il.com) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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