diff options
| author | Russ Anderson <rja@sgi.com> | 2007-09-20 13:59:12 -0500 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2007-10-12 15:17:44 -0700 |
| commit | 2bc5c282999af41042c2b703bf3a58ca1d7e3ee2 (patch) | |
| tree | fdf37ff750fdfd410e826945d361add25d60504e /arch/ia64 | |
| parent | 28eda5b8b434b65e5feb0c58a7477f3f290d72d4 (diff) | |
[IA64] Remove needless delay in MCA rendezvous
While testing the MCA recovery code, noticed that some machines would have a
five second delay rendezvousing cpus. What was happening is that
ia64_wait_for_slaves() would check to see if all the slave CPUs had
rendezvoused. If any had not, it would wait 1 millisecond then check again.
If any CPUs had still not rendezvoused, it would wait 5 seconds before
checking again.
On some configs the rendezvous takes more than 1 millisecond, causing the code
to wait the full 5 seconds, even though the last CPU rendezvoused after only
a few milliseconds.
The fix is to check every 1 millisecond to see if all the cpus have
rendezvoused. After 5 seconds the code concludes the CPUs will never
rendezvous (same as before).
The MCA code is, by definition, not performance critical, but a needless
delay of 5 seconds is senseless. The 5 seconds also adds up quickly
when running the error injection code in a loop.
This patch both simplifies the code and removes the needless delay.
Signed-off-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64')
| -rw-r--r-- | arch/ia64/kernel/mca.c | 41 |
1 files changed, 19 insertions, 22 deletions
diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c index 63b73f3d4c9f..92367faecbbf 100644 --- a/arch/ia64/kernel/mca.c +++ b/arch/ia64/kernel/mca.c @@ -1135,30 +1135,27 @@ no_mod: static void ia64_wait_for_slaves(int monarch, const char *type) { - int c, wait = 0, missing = 0; - for_each_online_cpu(c) { - if (c == monarch) - continue; - if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE) { - udelay(1000); /* short wait first */ - wait = 1; - break; - } - } - if (!wait) - goto all_in; - for_each_online_cpu(c) { - if (c == monarch) - continue; - if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE) { - udelay(5*1000000); /* wait 5 seconds for slaves (arbitrary) */ - if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE) - missing = 1; - break; + int c, i , wait; + + /* + * wait 5 seconds total for slaves (arbitrary) + */ + for (i = 0; i < 5000; i++) { + wait = 0; + for_each_online_cpu(c) { + if (c == monarch) + continue; + if (ia64_mc_info.imi_rendez_checkin[c] + == IA64_MCA_RENDEZ_CHECKIN_NOTDONE) { + udelay(1000); /* short wait */ + wait = 1; + break; + } } + if (!wait) + goto all_in; } - if (!missing) - goto all_in; + /* * Maybe slave(s) dead. Print buffered messages immediately. */ |