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Message-ID: <AANLkTimRXMivugXHJswrT5FA93PIjSjU-RneFKs1bkLL@mail.gmail.com> Date: Tue, 13 Jul 2010 20:32:17 +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> Subject: Re: Splice status On Tue, Jul 13, 2010 at 7:41 PM, Ofer Heifetz <oferh@...vell.com> wrote: > Hi, > > I wanted to let you know that I have been testing Samba splice on Marvell 6282 SoC on 2.6.35_rc3 and noticed that it gave worst performance than not using it and also noticed that on re-writing file the iowait is high. > > iometer using 2G file (file is created before test) > > Splice write cpu% iow% > ----------------------- > No 58 98 0 > Yes 14 100 48 > > iozone using 2G file (file created during test) > > Splice write cpu% iow% re-write cpu% iow% > ------------------------------------------- > No 35 85 4 58.2 70 0 > Yes 33 85 4 15.7 100 58 > > Any clue why splice introduces a high iowait? > I noticed samba uses up to 16K per splice syscall, changing the samba to try more did not help, so I guess it is a kernel limitation. > > -Ofer > What does the column write means? And what do you mean by saying re-write? Thanks. -- 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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