From mboxrd@z Thu Jan 1 00:00:00 1970 From: "John Stoffel" Subject: Re: Major network performance regression in 3.7 Date: Sun, 6 Jan 2013 16:55:20 -0500 Message-ID: <20713.62152.44264.204077@quad.stoffel.home> References: <1357490393.6919.267.camel@edumazet-glaptop> <20130106164416.GF16031@1wt.eu> <1357492255.6919.336.camel@edumazet-glaptop> <20130106173543.GB22432@1wt.eu> <1357497541.6919.519.camel@edumazet-glaptop> <1357497809.6919.529.camel@edumazet-glaptop> <1357498276.6919.547.camel@edumazet-glaptop> <1357498815.6919.570.camel@edumazet-glaptop> <20130106193410.GL16031@1wt.eu> <20713.61807.385486.594545@quad.stoffel.home> <20130106215200.GV16031@1wt.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: John Stoffel , Eric Dumazet , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Willy Tarreau Return-path: In-Reply-To: <20130106215200.GV16031@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org >>>>> "Willy" == Willy Tarreau writes: Willy> On Sun, Jan 06, 2013 at 04:49:35PM -0500, John Stoffel wrote: >> >>>>> "Willy" == Willy Tarreau writes: >> Willy> On Sun, Jan 06, 2013 at 11:00:15AM -0800, Eric Dumazet wrote: >> >> On Sun, 2013-01-06 at 10:51 -0800, Eric Dumazet wrote: >> >> > > >> >> > > (sd->len is usually 4096, which is expected, but sd->total_len value is >> >> > > huge in your case, so we always set the flag in fs/splice.c) >> >> > >> >> > I am testing : >> >> > >> >> > if (sd->len < sd->total_len && pipe->nrbufs > 1) >> >> > more |= MSG_SENDPAGE_NOTLAST; >> >> > >> >> >> >> Yes, this should fix the problem : >> >> >> >> If there is no following buffer in the pipe, we should not set NOTLAST. >> >> >> >> diff --git a/fs/splice.c b/fs/splice.c >> >> index 8890604..6909d89 100644 >> >> --- a/fs/splice.c >> >> +++ b/fs/splice.c >> >> @@ -696,8 +696,10 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe, >> >> return -EINVAL; >> >> >> >> more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; >> >> - if (sd->len < sd->total_len) >> >> + >> >> + if (sd->len < sd->total_len && pipe->nrbufs > 1) >> >> more |= MSG_SENDPAGE_NOTLAST; >> >> + >> >> return file->f_op->sendpage(file, buf->page, buf->offset, sd-> len, &pos, more); >> >> } >> Willy> OK it works like a charm here now ! I can't break it anymore, so it Willy> looks like you finally got it ! >> >> It's still broken, there's no comments in the code to explain all this >> magic to mere mortals! *grin* Willy> I would generally agree, but when Eric fixes such a thing, he Willy> generally goes with lengthy details in the commit message. I'm sure he will too, I just wanted to nudge him because while I sorta followed this discussion, I see lots of pain down the road if the code wasn't updated with some nice big fat comments. Great job finding this code and testing, testing, testing. John