Firewire node manager causes up to ~3.25s delay in freezing tasks.
PATCH 1/1 Firewire node manager causes up to ~3.25s delay in freezing tasks.
Hi all.
(Okay, having learnt that ieee1394 != bluetooth, I'll try again :>)
The firewire nodemanager function "nodemgr_host_thread" contains a loop that calls try_to_freeze near the top of the loop, but then delays for up to 3.25 seconds (plus time to do work) before getting back to the top of the loop. When starting a cycle post-boot, this doesn't seem to bite, but it is causing a noticeable delay at boot time, when freezing processes prior to starting to read the image.
The following patch adds invocation of try_to_freeze to the subloops that are used in the body of this function. With these additions, the time to freeze when starting to resume at boot time is virtually zero. I'm no expert on bluetooth, and so don't know that we shouldn't check the return value and jump back to the top of the loop or such like after being frozen, but I submit it for your consideration.
nodemgr.c | 2 ++ 1 file changed, 2 insertions(+)
drivers/ieee1394/nodemgr.c +2 -0
@@ -1685,6 +1685,7 @@ static int nodemgr_host_thread(void *dat g =get_hpsb_generation (host);for (i =0 ; i <4 ; i++) {msleep_interruptible (63 ); +try_to_freeze ();if (kthread_should_stop ()) goto exit;
@@ -1725,6 +1726,7 @@ static int nodemgr_host_thread(void *dat/* Sleep 3 seconds */ for (i =3000 /200 ; i; i--) {msleep_interruptible (200 ); +try_to_freeze ();if (kthread_should_stop ()) goto exit;
Quoted 10 lines · Nigel Cunningham
Hi all.
(Okay, having learnt that ieee1394 != bluetooth, I'll try again :>)
The firewire nodemanager function "
nodemgr_host_thread" contains a loop that callstry_to_freezenear the top of the loop, but then delays for up to 3.25 seconds (plus time to do work) before getting back to the top of the loop. When starting a cycle post-boot, this doesn't seem to bite, but it is causing a noticeable delay at boot time, when freezing processes prior to starting to read the image.
In 2.6.27 and less, these were only 0.25 seconds. The 3 additional seconds in 2.6.28-rc are my doing and sort of a regression. It occurs to me that I should send this patch to mainline before release.
Quoted 8 lines
The following patch adds invocation of
try_to_freezeto the subloops that are used in the body of this function. With these additions, the time to freeze when starting to resume at boot time is virtually zero. I'm no expert on bluetooth, and so don't know that we shouldn't check the return value and jump back to the top of the loop or such like after being frozen, but I submit it for your consideration.Signed-off-by Nigel Cunningham <[email protected]>
As far as I can tell, try_to_freeze() without any jump is correct.
drivers/ieee1394/nodemgr.c static int nodemgr_host_thread(void *dat · line 1691
Quoted 13 lines
nodemgr.c | 2 ++ 1 file changed, 2 insertions(+)diff -ruNp
710-nodemanager-freezing.patch-old/drivers/ieee1394/nodemgr.c710-nodemanager-freezing.patch-new/drivers/ieee1394/nodemgr.cdrivers/ieee1394/nodemgr.c +1
-0@@ -1685,6 +1685,7 @@ static int nodemgr_host_thread(void *dat g =get_hpsb_generation (host);for (i =0 ; i <4 ; i++) {msleep_interruptible (63 ); +try_to_freeze ();if (kthread_should_stop ()) goto exit;
Here we have the goal to proceed only >= 0.25s after the last bus reset happened. While the new try_to_freeze() held up nodemgr, another bus reset may happen. But we check for this later in the loop and handle it, so this is OK.
drivers/ieee1394/nodemgr.c static int nodemgr_host_thread(void *dat · line 1732
Quoted 8 lines
drivers/ieee1394/nodemgr.c +1
-0@@ -1725,6 +1726,7 @@ static int nodemgr_host_thread(void *dat/* Sleep 3 seconds */ for (i =3000 /200 ; i; i--) {msleep_interruptible (200 ); +try_to_freeze ();if (kthread_should_stop ()) goto exit;
Ditto, the rest of the loop catches the case that another bus reset occurred during the sleep or freeze.
Thanks for what appears to be a regression fix,
Signature · 3 lines
Stefan Richter -=====-==--- ==-- -=--= http://arcgraph.de/sr/
Quoted 10 lines · Nigel Cunningham
Hi all.
(Okay, having learnt that ieee1394 != bluetooth, I'll try again :>)
The firewire nodemanager function "
nodemgr_host_thread" contains a loop that callstry_to_freezenear the top of the loop, but then delays for up to 3.25 seconds (plus time to do work) before getting back to the top of the loop. When starting a cycle post-boot, this doesn't seem to bite, but it is causing a noticeable delay at boot time, when freezing processes prior to starting to read the image.
In 2.6.27 and less, these were only 0.25 seconds. The 3 additional seconds in 2.6.28-rc are my doing and sort of a regression. It occurs to me that I should send this patch to mainline before release.
Quoted 8 lines
The following patch adds invocation of
try_to_freezeto the subloops that are used in the body of this function. With these additions, the time to freeze when starting to resume at boot time is virtually zero. I'm no expert on bluetooth, and so don't know that we shouldn't check the return value and jump back to the top of the loop or such like after being frozen, but I submit it for your consideration.Signed-off-by Nigel Cunningham <[email protected]>
As far as I can tell, try_to_freeze() without any jump is correct.
drivers/ieee1394/nodemgr.c static int nodemgr_host_thread(void *dat · line 1691
Quoted 13 lines
nodemgr.c | 2 ++ 1 file changed, 2 insertions(+)diff -ruNp
710-nodemanager-freezing.patch-old/drivers/ieee1394/nodemgr.c710-nodemanager-freezing.patch-new/drivers/ieee1394/nodemgr.cdrivers/ieee1394/nodemgr.c +1
-0@@ -1685,6 +1685,7 @@ static int nodemgr_host_thread(void *dat g =get_hpsb_generation (host);for (i =0 ; i <4 ; i++) {msleep_interruptible (63 ); +try_to_freeze ();if (kthread_should_stop ()) goto exit;
Here we have the goal to proceed only >= 0.25s after the last bus reset happened. While the new try_to_freeze() held up nodemgr, another bus reset may happen. But we check for this later in the loop and handle it, so this is OK.
drivers/ieee1394/nodemgr.c static int nodemgr_host_thread(void *dat · line 1732
Quoted 8 lines
drivers/ieee1394/nodemgr.c +1
-0@@ -1725,6 +1726,7 @@ static int nodemgr_host_thread(void *dat/* Sleep 3 seconds */ for (i =3000 /200 ; i; i--) {msleep_interruptible (200 ); +try_to_freeze ();if (kthread_should_stop ()) goto exit;
Ditto, the rest of the loop catches the case that another bus reset occurred during the sleep or freeze.
Thanks for what appears to be a regression fix,
Signature · 3 lines
Stefan Richter -=====-==--- ==-- -=--= http://arcgraph.de/sr/