| Message ID | 1385106589-402-1-git-send-email-changxiangzhong@gmail.com |
|---|---|
| State | Rejected, archived |
| Delegated to: | David Miller |
| Headers | show |
On Fri, Nov 22, 2013 at 08:49:49AM +0100, Chang Xiangzhong wrote: > tsn_gap_acked is an important state flag in chunk, which indicates if the > chunk has been acked in gap reports before. SFR-CACC algorithm depends on this > variable. So set this at the end of each iteration, otherwise the SFR-CACC > algorithm would never be toggled. > > Signed-off-by: Chang Xiangzhong <changxiangzhong@gmail.com> > --- > net/sctp/outqueue.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c > index 1b494fa..bff828c 100644 > --- a/net/sctp/outqueue.c > +++ b/net/sctp/outqueue.c > @@ -1396,7 +1396,6 @@ static void sctp_check_transmitted(struct sctp_outq *q, > * while DATA was outstanding). > */ > if (!tchunk->tsn_gap_acked) { > - tchunk->tsn_gap_acked = 1; > if (TSN_lt(*highest_new_tsn_in_sack, tsn)) > *highest_new_tsn_in_sack = tsn; > bytes_acked += sctp_data_size(tchunk); > @@ -1460,6 +1459,8 @@ static void sctp_check_transmitted(struct sctp_outq *q, > */ > list_add_tail(lchunk, &tlist); > } > + > + tchunk->tsn_gap_acked = 1; > } else { > if (tchunk->tsn_gap_acked) { > pr_debug("%s: receiver reneged on data TSN:0x%x\n", > -- > 1.8.4.3 > > Acked-by: Neil Horman <nhorman@tuxdriver.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11/22/2013 02:49 AM, Chang Xiangzhong wrote: > tsn_gap_acked is an important state flag in chunk, which indicates if the > chunk has been acked in gap reports before. Actually, this bit indicates simply that the chunk has been acked. It doesn't state whether it's been acked in a gap report or via cumulative tsn. > SFR-CACC algorithm depends on this > variable. So set this at the end of each iteration, otherwise the SFR-CACC > algorithm would never be toggled. > > Signed-off-by: Chang Xiangzhong <changxiangzhong@gmail.com> > --- > net/sctp/outqueue.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c > index 1b494fa..bff828c 100644 > --- a/net/sctp/outqueue.c > +++ b/net/sctp/outqueue.c > @@ -1396,7 +1396,6 @@ static void sctp_check_transmitted(struct sctp_outq *q, > * while DATA was outstanding). > */ > if (!tchunk->tsn_gap_acked) { > - tchunk->tsn_gap_acked = 1; > if (TSN_lt(*highest_new_tsn_in_sack, tsn)) > *highest_new_tsn_in_sack = tsn; > bytes_acked += sctp_data_size(tchunk); > @@ -1460,6 +1459,8 @@ static void sctp_check_transmitted(struct sctp_outq *q, > */ > list_add_tail(lchunk, &tlist); > } > + > + tchunk->tsn_gap_acked = 1; The current code will set the state if it hasn't been set yet. Why is this needed? Now there is an issue with tracking highest_new_tsn_in_sack. The spec is a little vague on this, but the highest_new_tsn_in_sack only supposed to track tsns that have not been resent. If a tsn has been reneged, and then sent again, it is not considered 'new' thus should not count toward highest_new_tsn_in_sack. We currently do not track this right. -vlad -vlad > } else { > if (tchunk->tsn_gap_acked) { > pr_debug("%s: receiver reneged on data TSN:0x%x\n", > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11/22/2013 03:27 PM, Vlad Yasevich wrote: > On 11/22/2013 02:49 AM, Chang Xiangzhong wrote: >> tsn_gap_acked is an important state flag in chunk, which indicates if the >> chunk has been acked in gap reports before. > Actually, this bit indicates simply that the chunk has been acked. It > doesn't state whether it's been acked in a gap report or via cumulative tsn. Thanks for pointing this out. Sorry for not having made that clear. > >> SFR-CACC algorithm depends on this >> variable. So set this at the end of each iteration, otherwise the SFR-CACC >> algorithm would never be toggled. >> >> Signed-off-by: Chang Xiangzhong <changxiangzhong@gmail.com> >> --- >> net/sctp/outqueue.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c >> index 1b494fa..bff828c 100644 >> --- a/net/sctp/outqueue.c >> +++ b/net/sctp/outqueue.c >> @@ -1396,7 +1396,6 @@ static void sctp_check_transmitted(struct sctp_outq *q, >> * while DATA was outstanding). >> */ >> if (!tchunk->tsn_gap_acked) { >> - tchunk->tsn_gap_acked = 1; >> if (TSN_lt(*highest_new_tsn_in_sack, tsn)) >> *highest_new_tsn_in_sack = tsn; >> bytes_acked += sctp_data_size(tchunk); >> @@ -1460,6 +1459,8 @@ static void sctp_check_transmitted(struct sctp_outq *q, >> */ >> list_add_tail(lchunk, &tlist); >> } >> + >> + tchunk->tsn_gap_acked = 1; > The current code will set the state if it hasn't been set yet. Why is > this needed? Because in line 1420 ~ 1440 The SFR-CACC algorithms use tsn_gap_acked. That "if block" would never be triggered because the varaiable's been set. That's why I move the "state changing sentence" to the end of the iteration. > Now there is an issue with tracking highest_new_tsn_in_sack. The spec > is a little vague on this, but the highest_new_tsn_in_sack only supposed > to track tsns that have not been resent. If a tsn has been reneged, and > then sent again, it is not considered 'new' thus should not count > toward highest_new_tsn_in_sack. We currently do not track this right. I'll try to figure this out. > -vlad > > -vlad > >> } else { >> if (tchunk->tsn_gap_acked) { >> pr_debug("%s: receiver reneged on data TSN:0x%x\n", >> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11/22/2013 02:24 PM, Chang wrote: > > On 11/22/2013 03:27 PM, Vlad Yasevich wrote: >> On 11/22/2013 02:49 AM, Chang Xiangzhong wrote: >>> tsn_gap_acked is an important state flag in chunk, which indicates if >>> the >>> chunk has been acked in gap reports before. >> Actually, this bit indicates simply that the chunk has been acked. It >> doesn't state whether it's been acked in a gap report or via >> cumulative tsn. > Thanks for pointing this out. Sorry for not having made that clear. >> >>> SFR-CACC algorithm depends on this >>> variable. So set this at the end of each iteration, otherwise the >>> SFR-CACC >>> algorithm would never be toggled. >>> >>> Signed-off-by: Chang Xiangzhong <changxiangzhong@gmail.com> >>> --- >>> net/sctp/outqueue.c | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c >>> index 1b494fa..bff828c 100644 >>> --- a/net/sctp/outqueue.c >>> +++ b/net/sctp/outqueue.c >>> @@ -1396,7 +1396,6 @@ static void sctp_check_transmitted(struct >>> sctp_outq *q, >>> * while DATA was outstanding). >>> */ >>> if (!tchunk->tsn_gap_acked) { >>> - tchunk->tsn_gap_acked = 1; >>> if (TSN_lt(*highest_new_tsn_in_sack, tsn)) >>> *highest_new_tsn_in_sack = tsn; >>> bytes_acked += sctp_data_size(tchunk); >>> @@ -1460,6 +1459,8 @@ static void sctp_check_transmitted(struct >>> sctp_outq *q, >>> */ >>> list_add_tail(lchunk, &tlist); >>> } >>> + >>> + tchunk->tsn_gap_acked = 1; >> The current code will set the state if it hasn't been set yet. Why is >> this needed? > Because in line 1420 ~ 1440 The SFR-CACC algorithms use tsn_gap_acked. > That "if block" would never be triggered because the varaiable's been > set. That's why I move the "state changing sentence" to the end of the > iteration. >> Now there is an issue with tracking highest_new_tsn_in_sack. The spec >> is a little vague on this, but the highest_new_tsn_in_sack only supposed >> to track tsns that have not been resent. If a tsn has been reneged, and >> then sent again, it is not considered 'new' thus should not count >> toward highest_new_tsn_in_sack. We currently do not track this right. > I'll try to figure this out. So the solution that's been proposed before is to move the CACC block up and merge it with the !tsn_gap_acked block. This requires additional change though to only mark highest_new_tsn if the chunk has not been retransmitted (which you've added in a prior patch). -vlad >> -vlad >> >> -vlad >> >>> } else { >>> if (tchunk->tsn_gap_acked) { >>> pr_debug("%s: receiver reneged on data TSN:0x%x\n", >>> > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11/22/2013 11:48 PM, Vlad Yasevich wrote: > On 11/22/2013 02:24 PM, Chang wrote: >> On 11/22/2013 03:27 PM, Vlad Yasevich wrote: >>> On 11/22/2013 02:49 AM, Chang Xiangzhong wrote: >>>> tsn_gap_acked is an important state flag in chunk, which indicates if >>>> the >>>> chunk has been acked in gap reports before. >>> Actually, this bit indicates simply that the chunk has been acked. It >>> doesn't state whether it's been acked in a gap report or via >>> cumulative tsn. >> Thanks for pointing this out. Sorry for not having made that clear. >>>> SFR-CACC algorithm depends on this >>>> variable. So set this at the end of each iteration, otherwise the >>>> SFR-CACC >>>> algorithm would never be toggled. >>>> >>>> Signed-off-by: Chang Xiangzhong <changxiangzhong@gmail.com> >>>> --- >>>> net/sctp/outqueue.c | 3 ++- >>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c >>>> index 1b494fa..bff828c 100644 >>>> --- a/net/sctp/outqueue.c >>>> +++ b/net/sctp/outqueue.c >>>> @@ -1396,7 +1396,6 @@ static void sctp_check_transmitted(struct >>>> sctp_outq *q, >>>> * while DATA was outstanding). >>>> */ >>>> if (!tchunk->tsn_gap_acked) { >>>> - tchunk->tsn_gap_acked = 1; >>>> if (TSN_lt(*highest_new_tsn_in_sack, tsn)) >>>> *highest_new_tsn_in_sack = tsn; >>>> bytes_acked += sctp_data_size(tchunk); >>>> @@ -1460,6 +1459,8 @@ static void sctp_check_transmitted(struct >>>> sctp_outq *q, >>>> */ >>>> list_add_tail(lchunk, &tlist); >>>> } >>>> + >>>> + tchunk->tsn_gap_acked = 1; >>> The current code will set the state if it hasn't been set yet. Why is >>> this needed? >> Because in line 1420 ~ 1440 The SFR-CACC algorithms use tsn_gap_acked. >> That "if block" would never be triggered because the varaiable's been >> set. That's why I move the "state changing sentence" to the end of the >> iteration. >>> Now there is an issue with tracking highest_new_tsn_in_sack. The spec >>> is a little vague on this, but the highest_new_tsn_in_sack only supposed >>> to track tsns that have not been resent. If a tsn has been reneged, and >>> then sent again, it is not considered 'new' thus should not count >>> toward highest_new_tsn_in_sack. We currently do not track this right. >> I'll try to figure this out. > So the solution that's been proposed before is to move the CACC block up > and merge it with the !tsn_gap_acked block. This requires additional > change though to only mark highest_new_tsn if the chunk has not been > retransmitted (which you've added in a prior patch). > > -vlad Yeah, I've mixed that up with a prior patch. How was the previous patch? Was it approved? -chang >>> -vlad >>> >>> -vlad >>> >>>> } else { >>>> if (tchunk->tsn_gap_acked) { >>>> pr_debug("%s: receiver reneged on data TSN:0x%x\n", >>>> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, Could you please why a **reneged** newly acked TSN doesn't qualify the highest_new_tsn? What's the wrongs of doing that? I've been thinking a few scenarios, but I couldn't figure out what's wrong with that. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 11/23/2013 06:14 AM, Chang wrote: > Hi, > Could you please why a **reneged** newly acked TSN doesn't qualify the > highest_new_tsn? What's the wrongs of doing that? > > I've been thinking a few scenarios, but I couldn't figure out what's > wrong with that. > The spec is a bit conflicting on this topic. Here is what it says Section 7.2.4 Miss indications SHOULD follow the HTNA (Highest TSN Newly Acknowledged) algorithm. For each incoming SACK, miss indications are incremented only for missing TSNs prior to the highest TSN newly acknowledged in the SACK. A newly acknowledged DATA chunk is one not previously acknowledged in a SACK. But section 6.2.1 says: iii) If the SACK is missing a TSN that was previously acknowledged via a Gap Ack Block (e.g., the data receiver reneged on the data), then consider the corresponding DATA that might be possibly missing: Count one miss indication towards Fast Retransmit as described in Section 7.2.4, and if no retransmit timer is running for the destination address to which the DATA chunk was originally transmitted, then T3-rtx is started for that destination address. So, the question becomes does the reneged tsn update HTNA counter? It has been acked by a previous SACK, but 6.2.1 says to treat as missing. The more I look at this the more I think we should continue doing what we are doing which is following section 6.2.1. -vlad -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c index 1b494fa..bff828c 100644 --- a/net/sctp/outqueue.c +++ b/net/sctp/outqueue.c @@ -1396,7 +1396,6 @@ static void sctp_check_transmitted(struct sctp_outq *q, * while DATA was outstanding). */ if (!tchunk->tsn_gap_acked) { - tchunk->tsn_gap_acked = 1; if (TSN_lt(*highest_new_tsn_in_sack, tsn)) *highest_new_tsn_in_sack = tsn; bytes_acked += sctp_data_size(tchunk); @@ -1460,6 +1459,8 @@ static void sctp_check_transmitted(struct sctp_outq *q, */ list_add_tail(lchunk, &tlist); } + + tchunk->tsn_gap_acked = 1; } else { if (tchunk->tsn_gap_acked) { pr_debug("%s: receiver reneged on data TSN:0x%x\n",
tsn_gap_acked is an important state flag in chunk, which indicates if the chunk has been acked in gap reports before. SFR-CACC algorithm depends on this variable. So set this at the end of each iteration, otherwise the SFR-CACC algorithm would never be toggled. Signed-off-by: Chang Xiangzhong <changxiangzhong@gmail.com> --- net/sctp/outqueue.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)