On Fri, 21 Dec 2007, Ilpo Järvinen wrote:
> On Fri, 21 Dec 2007, Bill Fink wrote:
>
> > On Fri, 21 Dec 2007, Bill Fink wrote:
> >
> > > Or perhaps even:
> > >
> > > /* Ok, it looks like it is advisable to defer. */
> > > tp->tso_deferred = jiffies;
> > >
> > > /* need to return a non-ze
On Fri, 21 Dec 2007, Bill Fink wrote:
> On Fri, 21 Dec 2007, Bill Fink wrote:
>
> > Or perhaps even:
> >
> > /* Ok, it looks like it is advisable to defer. */
> > tp->tso_deferred = jiffies;
> >
> > /* need to return a non-zero value to defer, which means won't
> > * defer if
On Fri, 21 Dec 2007, Bill Fink wrote:
> Or perhaps even:
>
> /* Ok, it looks like it is advisable to defer. */
> tp->tso_deferred = jiffies;
>
> /* need to return a non-zero value to defer, which means won't
>* defer if jiffies == 0 but it's only a 1 in 4 billion event
On Fri, 21 Dec 2007, David Miller wrote:
> From: Herbert Xu <[EMAIL PROTECTED]>
> Date: Fri, 21 Dec 2007 17:29:27 +0800
>
> > On Fri, Dec 21, 2007 at 01:27:20AM -0800, David Miller wrote:
> > >
> > > It's two shifts, and this gets scheduled along with the other
> > > instructions on many cpus so
From: Herbert Xu <[EMAIL PROTECTED]>
Date: Fri, 21 Dec 2007 17:29:27 +0800
> On Fri, Dec 21, 2007 at 01:27:20AM -0800, David Miller wrote:
> >
> > It's two shifts, and this gets scheduled along with the other
> > instructions on many cpus so it's effectively free.
> >
> > I don't see why this is
On Fri, Dec 21, 2007 at 01:27:20AM -0800, David Miller wrote:
>
> It's two shifts, and this gets scheduled along with the other
> instructions on many cpus so it's effectively free.
>
> I don't see why this is even worth mentioning and discussing.
I totally agree. Two shifts are way better than
On Fri, 21 Dec 2007, Ilpo Järvinen wrote:
> On Fri, 21 Dec 2007, Bill Fink wrote:
>
> > If so it seems like a lot of unnecessary
> > work just to avoid a 1 in 4 billion event, since it's my understanding
> > that the whole tcp_tso_should_defer function is just an optimization
> > and not a critic
From: Bill Fink <[EMAIL PROTECTED]>
Date: Fri, 21 Dec 2007 03:06:48 -0500
> What's with all the shifting back and forth? Here with:
>
> ((jiffies<<1)>>1) - (tp->tso_deferred>>1)
>
> and later with:
>
> /* Ok, it looks like it is advisable to defer. */
> tp->tso_deferred = 1
On Fri, 21 Dec 2007, Bill Fink wrote:
> I meant to ask about this a while back but then got distracted by
> other things. But now since the subject has come up, I had a couple
> of more questions about this code.
>
> What's with all the shifting back and forth? Here with:
>
> ((jiffies<<
On Thu, 20 Dec 2007, David Miller wrote:
> From: "Ilpo_Järvinen" <[EMAIL PROTECTED]>
> Date: Thu, 20 Dec 2007 13:40:51 +0200 (EET)
>
> > [PATCH] [TCP]: Fix TSO deferring
> >
> > I'd say that most of what tcp_tso_should_defer had in between
> > there was dead code because of this.
> >
> > Signed
From: John Heffner <[EMAIL PROTECTED]>
Date: Thu, 20 Dec 2007 11:02:21 -0500
> David Miller wrote:
> > From: "Ilpo_Järvinen" <[EMAIL PROTECTED]>
> > Date: Thu, 20 Dec 2007 13:40:51 +0200 (EET)
> >
> >> [PATCH] [TCP]: Fix TSO deferring
> >>
> >> I'd say that most of what tcp_tso_should_defer had i
From: Herbert Xu <[EMAIL PROTECTED]>
Date: Thu, 20 Dec 2007 22:00:12 +0800
> On Thu, Dec 20, 2007 at 04:00:37AM -0800, David Miller wrote:
> >
> > In the most ideal sense, tcp_window_allows() should probably
> > be changed to only return MSS multiples.
> >
> > Unfortunately this would add an expe
David Miller wrote:
From: "Ilpo_Järvinen" <[EMAIL PROTECTED]>
Date: Thu, 20 Dec 2007 13:40:51 +0200 (EET)
[PATCH] [TCP]: Fix TSO deferring
I'd say that most of what tcp_tso_should_defer had in between
there was dead code because of this.
Signed-off-by: Ilpo Järvinen <[EMAIL PROTECTED]>
Yike
On Thu, Dec 20, 2007 at 04:00:37AM -0800, David Miller wrote:
>
> In the most ideal sense, tcp_window_allows() should probably
> be changed to only return MSS multiples.
>
> Unfortunately this would add an expensive modulo operation,
> however I think it would elimiate this problem case.
Well you
On Thu, 20 Dec 2007, David Miller wrote:
> From: "Ilpo_Järvinen" <[EMAIL PROTECTED]>
> Date: Thu, 20 Dec 2007 13:40:51 +0200 (EET)
>
> > That's not the only case, IMHO if there's odd boundary due to
> > snd_una+snd_wnd - skb->seq limit (done in tcp_window_allows()), we don't
> > consider it as
From: "Ilpo_Järvinen" <[EMAIL PROTECTED]>
Date: Thu, 20 Dec 2007 13:40:51 +0200 (EET)
> That's not the only case, IMHO if there's odd boundary due to
> snd_una+snd_wnd - skb->seq limit (done in tcp_window_allows()), we don't
> consider it as odd but break the skb at arbitary point resulting
> tw
From: "Ilpo_Järvinen" <[EMAIL PROTECTED]>
Date: Thu, 20 Dec 2007 13:40:51 +0200 (EET)
> [PATCH] [TCP]: Fix TSO deferring
>
> I'd say that most of what tcp_tso_should_defer had in between
> there was dead code because of this.
>
> Signed-off-by: Ilpo Järvinen <[EMAIL PROTECTED]>
Yikes!
John
On Wed, 19 Dec 2007, David Miller wrote:
> From: "Ilpo_Järvinen" <[EMAIL PROTECTED]>
> Date: Wed, 19 Dec 2007 23:46:33 +0200 (EET)
>
> > I'm not fully sure what's purpose of this code in tcp_write_xmit:
> >
> >if (skb->len < limit) {
> >uns
From: Herbert Xu <[EMAIL PROTECTED]>
Date: Thu, 20 Dec 2007 11:26:18 +0800
> Ilpo J??rvinen <[EMAIL PROTECTED]> wrote:
> >
> >> is the limitting factor? For latter IMHO this would be necessary:
> >>
> >> if (skb->len > limit)
> >> limit -= limit
From: "Ilpo_Järvinen" <[EMAIL PROTECTED]>
Date: Wed, 19 Dec 2007 23:46:33 +0200 (EET)
> I'm not fully sure what's purpose of this code in tcp_write_xmit:
>
>if (skb->len < limit) {
>unsigned int trim = skb->len % mss_now;
>
>
Ilpo J??rvinen <[EMAIL PROTECTED]> wrote:
>
>> is the limitting factor? For latter IMHO this would be necessary:
>>
>> if (skb->len > limit)
>> limit -= limit % mss_now;
Good catch! But how about putting this logic into tcp_window_allows
since t
On Wed, 19 Dec 2007, Ilpo Järvinen wrote:
> I'm not fully sure what's purpose of this code in tcp_write_xmit:
>
>if (skb->len < limit) {
>unsigned int trim = skb->len % mss_now;
>
>if (trim)
>
Hi all,
I'm not fully sure what's purpose of this code in tcp_write_xmit:
if (skb->len < limit) {
unsigned int trim = skb->len % mss_now;
if (trim)
limit = skb->len - trim;
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