| Message ID | 20240722145443.19104-1-chrubis@suse.cz |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v3] sched: starvation: Autocallibrate the timeout | expand |
Hi all, > Instead of hardcoding the values we attempt to measure the CPU speed and > set the runtime accordingly. Given that the difference in the duration > of the test when the kernel is buggy is about 30x we do not have to have > a precise callibration, just very rough estimate if we are running on a > server or small ARM board would suffice. > So we attempt to measure how long does a bussy loop take and base the > default timeout on that. On x86_64 CPUs the resulting runtime seems to > be between 2x and 10x of the actual runtime which seems to be in the > required range. > We also make sure to check the runtime at the end of the test because > the failures could have been masked by a timeout multiplier, i.e. if you > set LTP_TIMEOUT_MUL=10 the test would previously pass on a buggy kernel > as well. The side efect is that we now get better PASS/FAIL messages as > well. > Signed-off-by: Cyril Hrubis <chrubis@suse.cz> > --- > Changes in v3: > - Increased the CALLIBRATE_LOOPS a bit, since some of the numbers > reported by the linaro lab had the runtime very close to the > calculated runtime. Anders, Joe, can you please recheck? > - Removed some curly braces, as suggested by pvorel > - Added runtime check at the end of test to avoid false positives with > LTP_TIMEOUT_MUL. Great! LGTM. Reviewed-by: Petr Vorel <pvorel@suse.cz> Tested-by: Petr Vorel <pvorel@suse.cz> Tested on Tumbleweed (kernel 6.10.1): tst_tmpdir.c:316: TINFO: Using /tmp/LTP_starv8seE as tmpdir (tmpfs filesystem) tst_test.c:1806: TINFO: LTP version: 20240524 tst_test.c:1650: TINFO: Timeout per run is 0h 00m 30s starvation.c:71: TINFO: Setting affinity to CPU 0 tst_test.c:1658: TINFO: Updating max runtime to 0h 04m 00s tst_test.c:1650: TINFO: Timeout per run is 0h 04m 30s starvation.c:117: TPASS: wait_for_pid(child_pid) passed => test runs ~ 13s - 19s on aarch64, ppc64le and x86_64. Therefore not sure if 04m max runtime is good. I'll have tomorrow some tests on various SLES versions. Kind regards, Petr > .../kernel/sched/cfs-scheduler/starvation.c | 41 +++++++++++++++++-- > 1 file changed, 38 insertions(+), 3 deletions(-) > diff --git a/testcases/kernel/sched/cfs-scheduler/starvation.c b/testcases/kernel/sched/cfs-scheduler/starvation.c > index 9ac388fdc..e707e0865 100644 > --- a/testcases/kernel/sched/cfs-scheduler/starvation.c > +++ b/testcases/kernel/sched/cfs-scheduler/starvation.c > @@ -21,11 +21,38 @@ > #include <sched.h> > #include "tst_test.h" > +#include "tst_safe_clocks.h" > +#include "tst_timer.h" > static char *str_loop; > -static long loop = 2000000; > +static long loop = 1000000; > static char *str_timeout; > -static int timeout = 240; > +static int timeout; > + > +#define CALLIBRATE_LOOPS 120000000 > + > +static int callibrate(void) > +{ > + int i; > + struct timespec start, stop; > + long long diff; > + > + for (i = 0; i < CALLIBRATE_LOOPS; i++) > + __asm__ __volatile__ ("" : "+g" (i) : :); > + > + SAFE_CLOCK_GETTIME(CLOCK_MONOTONIC_RAW, &start); > + > + for (i = 0; i < CALLIBRATE_LOOPS; i++) > + __asm__ __volatile__ ("" : "+g" (i) : :); > + > + SAFE_CLOCK_GETTIME(CLOCK_MONOTONIC_RAW, &stop); > + > + diff = tst_timespec_diff_us(stop, start); > + > + tst_res(TINFO, "CPU did %i loops in %llius", CALLIBRATE_LOOPS, diff); > + > + return diff; > +} > static int wait_for_pid(pid_t pid) > { > @@ -78,6 +105,8 @@ static void setup(void) > if (tst_parse_int(str_timeout, &timeout, 1, INT_MAX)) > tst_brk(TBROK, "Invalid number of timeout '%s'", str_timeout); > + else > + timeout = callibrate() / 1000; > tst_set_max_runtime(timeout); > } > @@ -114,7 +143,13 @@ static void do_test(void) > sleep(1); > SAFE_KILL(child_pid, SIGTERM); > - TST_EXP_PASS(wait_for_pid(child_pid)); > + > + if (!tst_remaining_runtime()) > + tst_res(TFAIL, "Scheduller starvation reproduced."); > + else > + tst_res(TPASS, "Haven't reproduced scheduller starvation."); > + > + TST_EXP_PASS_SILENT(wait_for_pid(child_pid)); > } > static struct tst_test test = {
Hi! > tst_tmpdir.c:316: TINFO: Using /tmp/LTP_starv8seE as tmpdir (tmpfs filesystem) > tst_test.c:1806: TINFO: LTP version: 20240524 > tst_test.c:1650: TINFO: Timeout per run is 0h 00m 30s > starvation.c:71: TINFO: Setting affinity to CPU 0 > tst_test.c:1658: TINFO: Updating max runtime to 0h 04m 00s > tst_test.c:1650: TINFO: Timeout per run is 0h 04m 30s > starvation.c:117: TPASS: wait_for_pid(child_pid) passed > > => test runs ~ 13s - 19s on aarch64, ppc64le and x86_64. Therefore not sure if > 04m max runtime is good. Are you sure that you have run the test with the patch? Because it's missing the messages produced by the autocallibration and the wait_for_pid() should not be there after the patch.
> Hi! > > tst_tmpdir.c:316: TINFO: Using /tmp/LTP_starv8seE as tmpdir (tmpfs filesystem) > > tst_test.c:1806: TINFO: LTP version: 20240524 > > tst_test.c:1650: TINFO: Timeout per run is 0h 00m 30s > > starvation.c:71: TINFO: Setting affinity to CPU 0 > > tst_test.c:1658: TINFO: Updating max runtime to 0h 04m 00s > > tst_test.c:1650: TINFO: Timeout per run is 0h 04m 30s > > starvation.c:117: TPASS: wait_for_pid(child_pid) passed > > => test runs ~ 13s - 19s on aarch64, ppc64le and x86_64. Therefore not sure if > > 04m max runtime is good. > Are you sure that you have run the test with the patch? Ah, single missing variable, I tested just the master. I'm sorry, I'll retest. Kind regards, Petr > Because it's missing the messages produced by the autocallibration and > the wait_for_pid() should not be there after the patch.
Hi, > Hi! > > tst_tmpdir.c:316: TINFO: Using /tmp/LTP_starv8seE as tmpdir (tmpfs filesystem) > > tst_test.c:1806: TINFO: LTP version: 20240524 > > tst_test.c:1650: TINFO: Timeout per run is 0h 00m 30s > > starvation.c:71: TINFO: Setting affinity to CPU 0 > > tst_test.c:1658: TINFO: Updating max runtime to 0h 04m 00s > > tst_test.c:1650: TINFO: Timeout per run is 0h 04m 30s > > starvation.c:117: TPASS: wait_for_pid(child_pid) passed > > => test runs ~ 13s - 19s on aarch64, ppc64le and x86_64. Therefore not sure if > > 04m max runtime is good. OK, now testing with your patchset :) https://github.com/pevik/ltp/commit/0392e5142c5e8cb1d38dec9916a9f0118cf27afe All tests are on KVM. * aarch64 6.10.1-1-default (8s) tst_test.c:1650: TINFO: Timeout per run is 0h 00m 30s starvation.c:52: TINFO: CPU did 120000000 loops in 42654us tst_test.c:1658: TINFO: Updating max runtime to 0h 00m 42s tst_test.c:1650: TINFO: Timeout per run is 0h 01m 12s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * ppc64le 6.10.1-1-default (9s) ... tst_test.c:1650: TINFO: Timeout per run is 0h 00m 30s starvation.c:52: TINFO: CPU did 120000000 loops in 98081us tst_test.c:1658: TINFO: Updating max runtime to 0h 01m 38s => FYI HERE IS DIFFERENCE over 1 min tst_test.c:1650: TINFO: Timeout per run is 0h 02m 08s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * x86_64 6.10.1-1-default (10s) tst_test.c:1650: TINFO: Timeout per run is 0h 00m 30s starvation.c:52: TINFO: CPU did 120000000 loops in 41908us tst_test.c:1658: TINFO: Updating max runtime to 0h 00m 41s tst_test.c:1650: TINFO: Timeout per run is 0h 01m 11s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. Some SLES * s390x 6.4 (6s) starvation.c:52: TINFO: CPU did 120000000 loops in 53599us tst_test.c:1659: TINFO: Updating max runtime to 0h 00m 53s tst_test.c:1652: TINFO: Timeout per run is 0h 01m 23s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * s390x 6.4 (6s) starvation.c:52: TINFO: CPU did 120000000 loops in 53599us tst_test.c:1659: TINFO: Updating max runtime to 0h 00m 53s tst_test.c:1652: TINFO: Timeout per run is 0h 01m 23s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * x86_64 5.14.21 (5s) starvation.c:52: TINFO: CPU did 120000000 loops in 75176us tst_test.c:1659: TINFO: Updating max runtime to 0h 01m 15s tst_test.c:1652: TINFO: Timeout per run is 0h 01m 45s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * aarch64 5.14.21 (9s) starvation.c:52: TINFO: CPU did 120000000 loops in 42404us tst_test.c:1659: TINFO: Updating max runtime to 0h 00m 42s tst_test.c:1652: TINFO: Timeout per run is 0h 01m 12s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * ppc64le 5.14.21 (16s) starvation.c:52: TINFO: CPU did 120000000 loops in 147223us tst_test.c:1659: TINFO: Updating max runtime to 0h 02m 27s tst_test.c:1652: TINFO: Timeout per run is 0h 02m 57s => FYI HERE IS DIFFERENCE 2 min starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * aarch64 5.3.18 (8s) starvation.c:52: TINFO: CPU did 120000000 loops in 42382us tst_test.c:1659: TINFO: Updating max runtime to 0h 00m 42s tst_test.c:1652: TINFO: Timeout per run is 0h 01m 12s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * ppc64le 5.3.18 (50s) starvation.c:52: TINFO: CPU did 120000000 loops in 140564us tst_test.c:1659: TINFO: Updating max runtime to 0h 02m 20s tst_test.c:1652: TINFO: Timeout per run is 0h 02m 50s => FYI HERE IS DIFFERENCE 2 min starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * aarch64 4.12.14 (12s) starvation.c:52: TINFO: CPU did 120000000 loops in 55491us tst_test.c:1659: TINFO: Updating max runtime to 0h 00m 55s tst_test.c:1652: TINFO: Timeout per run is 0h 01m 25s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * ppc64le 4.12.14 (1m 9s FYI HIGHEST RUNTIME) starvation.c:52: TINFO: CPU did 120000000 loops in 147102us tst_test.c:1659: TINFO: Updating max runtime to 0h 02m 27s tst_test.c:1652: TINFO: Timeout per run is 0h 02m 57s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * s390x 4.12.14 (5s) starvation.c:52: TINFO: CPU did 120000000 loops in 49973us tst_test.c:1659: TINFO: Updating max runtime to 0h 00m 49s tst_test.c:1652: TINFO: Timeout per run is 0h 01m 19s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. * x86_64 4.4.180 (10s) starvation.c:52: TINFO: CPU did 120000000 loops in 37042us tst_test.c:1659: TINFO: Updating max runtime to 0h 00m 37s tst_test.c:1652: TINFO: Timeout per run is 0h 01m 07s starvation.c:150: TPASS: Haven't reproduced scheduller starvation. Kind regards, Petr
Hi! > OK, now testing with your patchset :) > https://github.com/pevik/ltp/commit/0392e5142c5e8cb1d38dec9916a9f0118cf27afe > > All tests are on KVM. Thanks for the testing, it looks like the estimation is between 2x and 10x of the actual runtime, which is perfectly within the expected range.
On Mon, 29 Jul 2024 at 22:51, Petr Vorel <pvorel@suse.cz> wrote: > > Hi all, > > > Instead of hardcoding the values we attempt to measure the CPU speed and > > set the runtime accordingly. Given that the difference in the duration > > of the test when the kernel is buggy is about 30x we do not have to have > > a precise callibration, just very rough estimate if we are running on a > > server or small ARM board would suffice. > > > So we attempt to measure how long does a bussy loop take and base the > > default timeout on that. On x86_64 CPUs the resulting runtime seems to > > be between 2x and 10x of the actual runtime which seems to be in the > > required range. > > > We also make sure to check the runtime at the end of the test because > > the failures could have been masked by a timeout multiplier, i.e. if you > > set LTP_TIMEOUT_MUL=10 the test would previously pass on a buggy kernel > > as well. The side efect is that we now get better PASS/FAIL messages as > > well. > > > Signed-off-by: Cyril Hrubis <chrubis@suse.cz> > > --- > > > Changes in v3: > > > - Increased the CALLIBRATE_LOOPS a bit, since some of the numbers > > reported by the linaro lab had the runtime very close to the > > calculated runtime. > > Anders, Joe, can you please recheck? I've tested this patch on 1 arm HW and 2 arm64 HW's. see the results below. arm HW: ===== [1;36mstarvation[0m ===== command: starvation [ 42.782470] /usr/local/bin/kirk[369]: starting test starvation (starvation) tst_test.c:1734: [1;34mTINFO: [0mLTP version: 20180118-5676-gc035435ba tst_test.c:1618: [1;34mTINFO: [0mTimeout per run is 0h 05m 24s starvation.c:84: [1;32mTPASS: [0msched_setaffinity(0, sizeof(mask), &mask) returned 0 starvation.c:52: [1;34mTINFO: [0mCPU did 120000000 loops in 106903us tst_test.c:1626: [1;34mTINFO: [0mUpdating max runtime to 0h 01m 46s tst_test.c:1618: [1;34mTINFO: [0mTimeout per run is 0h 07m 10s starvation.c:133: [1;32mTPASS: [0mHaven't reproduced scheduller starvation. Summary: passed 2 failed 0 broken 0 skipped 0 warnings 0 Duration: 1m 2s arm64 HW1: ===== [1;36mstarvation[0m ===== command: starvation [ 52.326682] /usr/local/bin/kirk[371]: starting test starvation (starvation) [ 52.326682] /usr/local/bin/kirk[371]: starting test starvation (starvation) tst_test.c:1734: [1;34mTINFO: [0mLTP version: 20180118-5676-gc035435ba tst_test.c:1618: [1;34mTINFO: [0mTimeout per run is 0h 05m 24s starvation.c:84: [1;32mTPASS: [0msched_setaffinity(0, sizeof(mask), &mask) returned 0 starvation.c:52: [1;34mTINFO: [0mCPU did 120000000 loops in 170664us tst_test.c:1626: [1;34mTINFO: [0mUpdating max runtime to 0h 02m 50s tst_test.c:1618: [1;34mTINFO: [0mTimeout per run is 0h 08m 14s starvation.c:133: [1;32mTPASS: [0mHaven't reproduced scheduller starvation. Summary: passed 2 failed 0 broken 0 skipped 0 warnings 0 Duration: 1m 31s arm64 HW2: ===== [1;36mstarvation[0m ===== command: starvation [ 25.461437] /usr/local/bin/kirk[781]: starting test starvation (starvation) tst_test.c:1734: [1;34mTINFO: [0mLTP version: 20180118-5676-gc035435ba tst_test.c:1618: [1;34mTINFO: [0mTimeout per run is 0h 05m 24s starvation.c:84: [1;32mTPASS: [0msched_setaffinity(0, sizeof(mask), &mask) returned 0 starvation.c:52: [1;34mTINFO: [0mCPU did 120000000 loops in 136451us tst_test.c:1626: [1;34mTINFO: [0mUpdating max runtime to 0h 02m 16s tst_test.c:1618: [1;34mTINFO: [0mTimeout per run is 0h 07m 40s [ 29.165003] sd 0:0:0:0: [sda] Starting disk [ 35.815791] sd 0:0:0:0: [sda] Starting disk [ 39.911757] sd 0:0:0:0: [sda] Starting disk [ 47.079469] sd 0:0:0:0: [sda] Starting disk [ 52.716832] sd 0:0:0:0: [sda] Starting disk [ 57.831781] sd 0:0:0:0: [sda] Starting disk [ 63.975740] sd 0:0:0:0: [sda] Starting disk [ 69.095887] sd 0:0:0:0: [sda] Starting disk [ 74.983623] sd 0:0:0:0: [sda] Starting disk [ 77.799749] sd 0:0:0:0: [sda] Starting disk [ 80.871712] sd 0:0:0:0: [sda] Starting disk [ 87.015762] sd 0:0:0:0: [sda] Starting disk [ 92.903786] sd 0:0:0:0: [sda] Starting disk starvation.c:133: [1;32mTPASS: [0mHaven't reproduced scheduller starvation. Summary: passed 2 failed 0 broken 0 skipped 0 warnings 0 Duration: 1m 7s Tested-by: Anders Roxell <anders.roxell@linaro.org> Cheers, Anders > > > - Removed some curly braces, as suggested by pvorel > > > - Added runtime check at the end of test to avoid false positives with > > LTP_TIMEOUT_MUL. > > Great! > > LGTM. > > Reviewed-by: Petr Vorel <pvorel@suse.cz> > > Tested-by: Petr Vorel <pvorel@suse.cz> > > Tested on Tumbleweed (kernel 6.10.1): > > tst_tmpdir.c:316: TINFO: Using /tmp/LTP_starv8seE as tmpdir (tmpfs filesystem) > tst_test.c:1806: TINFO: LTP version: 20240524 > tst_test.c:1650: TINFO: Timeout per run is 0h 00m 30s > starvation.c:71: TINFO: Setting affinity to CPU 0 > tst_test.c:1658: TINFO: Updating max runtime to 0h 04m 00s > tst_test.c:1650: TINFO: Timeout per run is 0h 04m 30s > starvation.c:117: TPASS: wait_for_pid(child_pid) passed > > => test runs ~ 13s - 19s on aarch64, ppc64le and x86_64. Therefore not sure if > 04m max runtime is good. > > I'll have tomorrow some tests on various SLES versions. > > Kind regards, > Petr > > > .../kernel/sched/cfs-scheduler/starvation.c | 41 +++++++++++++++++-- > > 1 file changed, 38 insertions(+), 3 deletions(-) > > > diff --git a/testcases/kernel/sched/cfs-scheduler/starvation.c b/testcases/kernel/sched/cfs-scheduler/starvation.c > > index 9ac388fdc..e707e0865 100644 > > --- a/testcases/kernel/sched/cfs-scheduler/starvation.c > > +++ b/testcases/kernel/sched/cfs-scheduler/starvation.c > > @@ -21,11 +21,38 @@ > > #include <sched.h> > > > #include "tst_test.h" > > +#include "tst_safe_clocks.h" > > +#include "tst_timer.h" > > > static char *str_loop; > > -static long loop = 2000000; > > +static long loop = 1000000; > > static char *str_timeout; > > -static int timeout = 240; > > +static int timeout; > > + > > +#define CALLIBRATE_LOOPS 120000000 > > + > > +static int callibrate(void) > > +{ > > + int i; > > + struct timespec start, stop; > > + long long diff; > > + > > + for (i = 0; i < CALLIBRATE_LOOPS; i++) > > + __asm__ __volatile__ ("" : "+g" (i) : :); > > + > > + SAFE_CLOCK_GETTIME(CLOCK_MONOTONIC_RAW, &start); > > + > > + for (i = 0; i < CALLIBRATE_LOOPS; i++) > > + __asm__ __volatile__ ("" : "+g" (i) : :); > > + > > + SAFE_CLOCK_GETTIME(CLOCK_MONOTONIC_RAW, &stop); > > + > > + diff = tst_timespec_diff_us(stop, start); > > + > > + tst_res(TINFO, "CPU did %i loops in %llius", CALLIBRATE_LOOPS, diff); > > + > > + return diff; > > +} > > > static int wait_for_pid(pid_t pid) > > { > > @@ -78,6 +105,8 @@ static void setup(void) > > > if (tst_parse_int(str_timeout, &timeout, 1, INT_MAX)) > > tst_brk(TBROK, "Invalid number of timeout '%s'", str_timeout); > > + else > > + timeout = callibrate() / 1000; > > > tst_set_max_runtime(timeout); > > } > > @@ -114,7 +143,13 @@ static void do_test(void) > > sleep(1); > > > SAFE_KILL(child_pid, SIGTERM); > > - TST_EXP_PASS(wait_for_pid(child_pid)); > > + > > + if (!tst_remaining_runtime()) > > + tst_res(TFAIL, "Scheduller starvation reproduced."); > > + else > > + tst_res(TPASS, "Haven't reproduced scheduller starvation."); > > + > > + TST_EXP_PASS_SILENT(wait_for_pid(child_pid)); > > } > > > static struct tst_test test = {
Hi! Pushed, thanks for the reviews and testing.
diff --git a/testcases/kernel/sched/cfs-scheduler/starvation.c b/testcases/kernel/sched/cfs-scheduler/starvation.c index 9ac388fdc..e707e0865 100644 --- a/testcases/kernel/sched/cfs-scheduler/starvation.c +++ b/testcases/kernel/sched/cfs-scheduler/starvation.c @@ -21,11 +21,38 @@ #include <sched.h> #include "tst_test.h" +#include "tst_safe_clocks.h" +#include "tst_timer.h" static char *str_loop; -static long loop = 2000000; +static long loop = 1000000; static char *str_timeout; -static int timeout = 240; +static int timeout; + +#define CALLIBRATE_LOOPS 120000000 + +static int callibrate(void) +{ + int i; + struct timespec start, stop; + long long diff; + + for (i = 0; i < CALLIBRATE_LOOPS; i++) + __asm__ __volatile__ ("" : "+g" (i) : :); + + SAFE_CLOCK_GETTIME(CLOCK_MONOTONIC_RAW, &start); + + for (i = 0; i < CALLIBRATE_LOOPS; i++) + __asm__ __volatile__ ("" : "+g" (i) : :); + + SAFE_CLOCK_GETTIME(CLOCK_MONOTONIC_RAW, &stop); + + diff = tst_timespec_diff_us(stop, start); + + tst_res(TINFO, "CPU did %i loops in %llius", CALLIBRATE_LOOPS, diff); + + return diff; +} static int wait_for_pid(pid_t pid) { @@ -78,6 +105,8 @@ static void setup(void) if (tst_parse_int(str_timeout, &timeout, 1, INT_MAX)) tst_brk(TBROK, "Invalid number of timeout '%s'", str_timeout); + else + timeout = callibrate() / 1000; tst_set_max_runtime(timeout); } @@ -114,7 +143,13 @@ static void do_test(void) sleep(1); SAFE_KILL(child_pid, SIGTERM); - TST_EXP_PASS(wait_for_pid(child_pid)); + + if (!tst_remaining_runtime()) + tst_res(TFAIL, "Scheduller starvation reproduced."); + else + tst_res(TPASS, "Haven't reproduced scheduller starvation."); + + TST_EXP_PASS_SILENT(wait_for_pid(child_pid)); } static struct tst_test test = {
Instead of hardcoding the values we attempt to measure the CPU speed and set the runtime accordingly. Given that the difference in the duration of the test when the kernel is buggy is about 30x we do not have to have a precise callibration, just very rough estimate if we are running on a server or small ARM board would suffice. So we attempt to measure how long does a bussy loop take and base the default timeout on that. On x86_64 CPUs the resulting runtime seems to be between 2x and 10x of the actual runtime which seems to be in the required range. We also make sure to check the runtime at the end of the test because the failures could have been masked by a timeout multiplier, i.e. if you set LTP_TIMEOUT_MUL=10 the test would previously pass on a buggy kernel as well. The side efect is that we now get better PASS/FAIL messages as well. Signed-off-by: Cyril Hrubis <chrubis@suse.cz> --- Changes in v3: - Increased the CALLIBRATE_LOOPS a bit, since some of the numbers reported by the linaro lab had the runtime very close to the calculated runtime. - Removed some curly braces, as suggested by pvorel - Added runtime check at the end of test to avoid false positives with LTP_TIMEOUT_MUL. .../kernel/sched/cfs-scheduler/starvation.c | 41 +++++++++++++++++-- 1 file changed, 38 insertions(+), 3 deletions(-)