On 4/24/18 8:19 PM, Alan Kao wrote:
Hi Atish, Palmer,
On Tue, Apr 24, 2018 at 06:15:49PM -0700, Atish Patra wrote:
On 4/24/18 5:29 PM, Palmer Dabbelt wrote:
On Tue, 24 Apr 2018 15:16:16 PDT (-0700), atish.patra@xxxxxxx wrote:
On 4/24/18 12:44 PM, Palmer Dabbelt wrote:
On Tue, 24 Apr 2018 12:27:26 PDT (-0700), atish.patra@xxxxxxx wrote:
On 4/24/18 11:07 AM, Atish Patra wrote:
On 4/19/18 4:28 PM, Alan Kao wrote:
However, I got an rcu-stall for the test "47: Event times".
# ./perf test -v 47
Got it working. The test tries to attach the event to CPU0 which doesn't
exist in HighFive Unleashed. Changing it to cpu1 works.
diff --git a/tools/perf/tests/event-times.c b/tools/perf/tests/event-times.c
index 1a2686f..eb11632f 100644
--- a/tools/perf/tests/event-times.c
+++ b/tools/perf/tests/event-times.c
@@ -113,9 +113,9 @@ static int attach__cpu_disabled(struct perf_evlist
*evlist)
struct cpu_map *cpus;
int err;
- pr_debug("attaching to CPU 0 as enabled\n");
+ pr_debug("attaching to CPU 1 as disabled\n");
- cpus = cpu_map__new("0");
+ cpus = cpu_map__new("1");
if (cpus == NULL) {
pr_debug("failed to call cpu_map__new\n");
return -1;
@@ -142,9 +142,9 @@ static int attach__cpu_enabled(struct perf_evlist
*evlist)
struct cpu_map *cpus;
int err;
- pr_debug("attaching to CPU 0 as enabled\n");
+ pr_debug("attaching to CPU 1 as enabled\n");
- cpus = cpu_map__new("0");
+ cpus = cpu_map__new("1");
if (cpus == NULL) {
pr_debug("failed to call cpu_map__new\n");
return -1;
Palmer,
Would it be better to officially document it somewhere that CPU0 doesn't
exist in the HighFive Unleashed board ?
I fear that there will be other standard tests/code path that may fail
because of inherent assumption of cpu0 presence.
I think the best way to fix this is to just have BBL (or whatever the
bootloader is) renumber the CPUs so they're contiguous and begin with 0.
Do you mean BBL will update the device tree that kernel eventually parse
and set the hart id?
Sounds good to me unless it acts as a big hack in future boot loaders.
Right now the machine-mode and supervisor-mode hart IDs are logically separate:
the bootloader just provides the hart ID as a register argument when starting
the kernel.
Yes.
BBL already needs to enumerate the harts by looking through the
device tree for various other reasons (at least to mask off the harts that
Linux doesn't support), so it's not that much effort to just maintain a mapping
>from supervisor-mode hart IDs to machine-mode hart IDs.
But Linux also parses the device tree to get hart ID in
riscv_of_processor_hart(). This is used to setup the possible/present cpu
map in setup_smp().
Thus, Linux also need to see a device tree with cpu0-3 instead of cpu1-4.
Otherwise, present cpu map will be incorrect. Isn't it ?
I have some patches floating around that do this, but appear to do it
incorrectly enough that nothing boots so maybe I'm missing something that makes
this complicated :).
Just a wild guess: May be the because of the above reason ;)
Thanks for the test and discussion. It looks like am implementation issue from
Unleash, so ... is there anything I should fix and provide a further patch?
Nope. Nothing for this issue.
The fix for this issue should be either in bbl or kernel as a separate
patch.
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