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-off-by: Ilpo
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:
((jiffies1)1) -
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:
((jiffies1)1) - (tp-tso_deferred1)
and later with:
/* Ok, it looks like it is advisable to defer. */
tp-tso_deferred = 1 | (jiffies1);
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 criticality to
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 a
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 even worth
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 it's
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, 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 jiffies == 0 but
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-zero value to defer, which
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) {
unsigned int trim =
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, we've
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
two small
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 odd but break
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 only
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]
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 expensive modulo
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 in between
there was
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)
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 then you can
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;
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 % mss_now;
Good
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