Messages in this thread Patch in this message | | | Date | Wed, 25 Jul 2007 11:23:42 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] fix the softlockup watchdog to actually work |
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* Andrew Morton <akpm@linux-foundation.org> wrote:
> > * 2^30ns == 1.074s. > > */ > > -static unsigned long get_timestamp(void) > > +static unsigned long get_timestamp(int this_cpu) > > { > > - return sched_clock() >> 30; /* 2^30 ~= 10^9 */ > > + return cpu_clock(this_cpu) >> 30; /* 2^30 ~= 10^9 */ > > } > > > > void touch_softlockup_watchdog(void) > > { > > - __raw_get_cpu_var(touch_timestamp) = get_timestamp(); > > + int this_cpu = raw_smp_processor_id(); > > + > > + per_cpu(touch_timestamp, this_cpu) = get_timestamp(this_cpu); > > } > > EXPORT_SYMBOL(touch_softlockup_watchdog); > > > > @@ -95,7 +97,7 @@ void softlockup_tick(void) > > return; > > argh. afacit this was never sent, except as part of some jumbopatch > called "sched: implement cpu_clock(cpu) high-speed time source". > > That patch helped. > > It's all a plot.
sorry, it's really my fault: i decoupled it from the jumbopatch (so that the new API could go in first) but forgot to re-send that crutial bit. There's also the patch below (Jens Cc:-ed) to update blktrace. I guess i should do a softlockup.git tree to avoid such foul-ups in the future.
Ingo
-----------------------> Subject: blktrace: use cpu_clock() instead of sched_clock() From: Ingo Molnar <mingo@elte.hu>
use cpu_clock() instead of sched_clock(). (the latter is not a proper clock-source)
Signed-off-by: Ingo Molnar <mingo@elte.hu> --- block/blktrace.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)
Index: linux/block/blktrace.c =================================================================== --- linux.orig/block/blktrace.c +++ linux/block/blktrace.c @@ -41,7 +41,7 @@ static void trace_note(struct blk_trace const int cpu = smp_processor_id(); t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; - t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu); + t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu); t->device = bt->dev; t->action = action; t->pid = pid; @@ -159,7 +159,7 @@ void __blk_add_trace(struct blk_trace *b t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; t->sequence = ++(*sequence); - t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu); + t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu); t->sector = sector; t->bytes = bytes; t->action = what; @@ -488,17 +488,17 @@ void blk_trace_shutdown(request_queue_t } /* - * Average offset over two calls to sched_clock() with a gettimeofday() + * Average offset over two calls to cpu_clock() with a gettimeofday() * in the middle */ -static void blk_check_time(unsigned long long *t) +static void blk_check_time(unsigned long long *t, int this_cpu) { unsigned long long a, b; struct timeval tv; - a = sched_clock(); + a = cpu_clock(this_cpu); do_gettimeofday(&tv); - b = sched_clock(); + b = cpu_clock(this_cpu); *t = tv.tv_sec * 1000000000 + tv.tv_usec * 1000; *t -= (a + b) / 2; @@ -510,16 +510,16 @@ static void blk_check_time(unsigned long static void blk_trace_check_cpu_time(void *data) { unsigned long long *t; - int cpu = get_cpu(); + int this_cpu = get_cpu(); - t = &per_cpu(blk_trace_cpu_offset, cpu); + t = &per_cpu(blk_trace_cpu_offset, this_cpu); /* * Just call it twice, hopefully the second call will be cache hot * and a little more precise */ - blk_check_time(t); - blk_check_time(t); + blk_check_time(t, this_cpu); + blk_check_time(t, this_cpu); put_cpu(); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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