* [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test
@ 2022-09-01 15:09 Nico Boehr
2022-09-01 15:09 ` [kvm-unit-tests PATCH v2 1/2] lib/s390x: time: add wrapper for stckf Nico Boehr
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Nico Boehr @ 2022-09-01 15:09 UTC (permalink / raw)
To: kvm; +Cc: frankja, imbrenda, thuth
v1->v2:
---
* add missing cc clobber, fix constraints for get_clock_us() (thanks
Thomas)
* avoid array and use pointer to const char* (thanks Thomas)
* add comment why testing nop makes sense (thanks Thomas)
* rework constraints and clobbers (thanks Thomas)
Sometimes, it is useful to measure the exit time of certain instructions
to e.g. identify performance regressions in instructions emulated by the
hypervisor.
This series adds a test which executes some instructions and measures
their execution time. Since their execution time depends a lot on the
environment at hand, all tests are reported as PASS currently.
The point of this series is not so much the instructions which have been
chosen here (but your ideas are welcome), but rather the general
question whether it makes sense to have a test like this in
kvm-unit-tests.
Nico Boehr (2):
lib/s390x: time: add wrapper for stckf
s390x: add exittime tests
lib/s390x/asm/time.h | 11 +-
s390x/Makefile | 1 +
s390x/exittime.c | 255 +++++++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 4 +
4 files changed, 270 insertions(+), 1 deletion(-)
create mode 100644 s390x/exittime.c
--
2.36.1
^ permalink raw reply [flat|nested] 7+ messages in thread* [kvm-unit-tests PATCH v2 1/2] lib/s390x: time: add wrapper for stckf 2022-09-01 15:09 [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test Nico Boehr @ 2022-09-01 15:09 ` Nico Boehr 2022-10-06 11:16 ` Claudio Imbrenda 2022-09-01 15:09 ` [kvm-unit-tests PATCH v2 2/2] s390x: add exittime tests Nico Boehr 2022-10-06 11:18 ` [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test Claudio Imbrenda 2 siblings, 1 reply; 7+ messages in thread From: Nico Boehr @ 2022-09-01 15:09 UTC (permalink / raw) To: kvm; +Cc: frankja, imbrenda, thuth Upcoming changes will do performance measurements of instructions. Since stck is designed to return unique values even on concurrent calls, it is unsuited for performance measurements. stckf should be used in this case. While touching that code, also add a missing cc clobber in get_clock_us() and avoid the memory clobber by moving the clock value to the output operands. Hence, add a nice wrapper for stckf to the time library. Signed-off-by: Nico Boehr <nrb@linux.ibm.com> --- lib/s390x/asm/time.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/lib/s390x/asm/time.h b/lib/s390x/asm/time.h index 7652a151e87a..8d2327a40541 100644 --- a/lib/s390x/asm/time.h +++ b/lib/s390x/asm/time.h @@ -14,11 +14,20 @@ #define STCK_SHIFT_US (63 - 51) #define STCK_MAX ((1UL << 52) - 1) +static inline uint64_t get_clock_fast(void) +{ + uint64_t clk; + + asm volatile(" stckf %0 " : "=Q"(clk) : : "cc"); + + return clk; +} + static inline uint64_t get_clock_us(void) { uint64_t clk; - asm volatile(" stck %0 " : : "Q"(clk) : "memory"); + asm volatile(" stck %0 " : "=Q"(clk) : : "cc"); return clk >> STCK_SHIFT_US; } -- 2.36.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [kvm-unit-tests PATCH v2 1/2] lib/s390x: time: add wrapper for stckf 2022-09-01 15:09 ` [kvm-unit-tests PATCH v2 1/2] lib/s390x: time: add wrapper for stckf Nico Boehr @ 2022-10-06 11:16 ` Claudio Imbrenda 0 siblings, 0 replies; 7+ messages in thread From: Claudio Imbrenda @ 2022-10-06 11:16 UTC (permalink / raw) To: Nico Boehr; +Cc: kvm, frankja, thuth On Thu, 1 Sep 2022 17:09:55 +0200 Nico Boehr <nrb@linux.ibm.com> wrote: > Upcoming changes will do performance measurements of instructions. Since > stck is designed to return unique values even on concurrent calls, it is > unsuited for performance measurements. stckf should be used in this > case. > > While touching that code, also add a missing cc clobber in > get_clock_us() and avoid the memory clobber by moving the clock value to > the output operands. > > Hence, add a nice wrapper for stckf to the time library. > > Signed-off-by: Nico Boehr <nrb@linux.ibm.com> > --- > lib/s390x/asm/time.h | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/lib/s390x/asm/time.h b/lib/s390x/asm/time.h > index 7652a151e87a..8d2327a40541 100644 > --- a/lib/s390x/asm/time.h > +++ b/lib/s390x/asm/time.h > @@ -14,11 +14,20 @@ > #define STCK_SHIFT_US (63 - 51) > #define STCK_MAX ((1UL << 52) - 1) > > +static inline uint64_t get_clock_fast(void) > +{ > + uint64_t clk; > + > + asm volatile(" stckf %0 " : "=Q"(clk) : : "cc"); > + > + return clk; > +} > + > static inline uint64_t get_clock_us(void) > { > uint64_t clk; > > - asm volatile(" stck %0 " : : "Q"(clk) : "memory"); > + asm volatile(" stck %0 " : "=Q"(clk) : : "cc"); this fix is not needed if you use the wrapper for stck from your other patch series > > return clk >> STCK_SHIFT_US; > } ^ permalink raw reply [flat|nested] 7+ messages in thread
* [kvm-unit-tests PATCH v2 2/2] s390x: add exittime tests 2022-09-01 15:09 [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test Nico Boehr 2022-09-01 15:09 ` [kvm-unit-tests PATCH v2 1/2] lib/s390x: time: add wrapper for stckf Nico Boehr @ 2022-09-01 15:09 ` Nico Boehr 2022-10-06 11:15 ` Claudio Imbrenda 2022-10-06 11:18 ` [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test Claudio Imbrenda 2 siblings, 1 reply; 7+ messages in thread From: Nico Boehr @ 2022-09-01 15:09 UTC (permalink / raw) To: kvm; +Cc: frankja, imbrenda, thuth Add a test to measure the execution time of several instructions. This can be helpful in finding performance regressions in hypervisor code. All tests are currently reported as PASS, since the baseline for their execution time depends on the respective environment and since needs to be determined on a case-by-case basis. Signed-off-by: Nico Boehr <nrb@linux.ibm.com> --- s390x/Makefile | 1 + s390x/exittime.c | 255 ++++++++++++++++++++++++++++++++++++++++++++ s390x/unittests.cfg | 4 + 3 files changed, 260 insertions(+) create mode 100644 s390x/exittime.c diff --git a/s390x/Makefile b/s390x/Makefile index efd5e0c13102..5dcac244767f 100644 --- a/s390x/Makefile +++ b/s390x/Makefile @@ -34,6 +34,7 @@ tests += $(TEST_DIR)/migration.elf tests += $(TEST_DIR)/pv-attest.elf tests += $(TEST_DIR)/migration-cmm.elf tests += $(TEST_DIR)/migration-skey.elf +tests += $(TEST_DIR)/exittime.elf pv-tests += $(TEST_DIR)/pv-diags.elf diff --git a/s390x/exittime.c b/s390x/exittime.c new file mode 100644 index 000000000000..543c82ff3906 --- /dev/null +++ b/s390x/exittime.c @@ -0,0 +1,255 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Measure run time of various instructions. Can be used to find runtime + * regressions of instructions which cause exits. + * + * Copyright IBM Corp. 2022 + * + * Authors: + * Nico Boehr <nrb@linux.ibm.com> + */ +#include <libcflat.h> +#include <smp.h> +#include <sclp.h> +#include <asm/time.h> +#include <asm/sigp.h> +#include <asm/interrupt.h> +#include <asm/page.h> + +char pagebuf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); + +static void test_sigp_sense_running(long destcpu) +{ + smp_sigp(destcpu, SIGP_SENSE_RUNNING, 0, NULL); +} + +static void test_nop(long ignore) +{ + /* nops don't trap into the hypervisor, so let's test them for reference */ + asm volatile("nop" : : : "memory"); +} + +static void test_diag9c(long destcpu) +{ + asm volatile("diag %[destcpu],0,0x9c" + : + : [destcpu] "d" (destcpu) + : + ); +} + +static long setup_get_this_cpuaddr(long ignore) +{ + return stap(); +} + +static void test_diag44(long ignore) +{ + asm volatile("diag 0,0,0x44"); +} + +static void test_stnsm(long ignore) +{ + int out; + + asm volatile( + "stnsm %[out],0xff" + : [out] "=Q" (out) + : + ); +} + +static void test_stosm(long ignore) +{ + int out; + + asm volatile( + "stosm %[out],0" + : [out] "=Q" (out) + : + ); +} + +static long setup_ssm(long ignore) +{ + long system_mask = 0; + + asm volatile( + "stosm %[system_mask],0" + : [system_mask] "=Q" (system_mask) + : + : + ); + + return system_mask; +} + +static void test_ssm(long old_system_mask) +{ + asm volatile( + "ssm %[old_system_mask]" + : + : [old_system_mask] "Q" (old_system_mask) + : + ); +} + +static long setup_lctl4(long ignore) +{ + long ctl4_orig = 0; + + asm volatile( + "stctg 4,4,%[ctl4_orig]" + : [ctl4_orig] "=S" (ctl4_orig) + : + : + ); + + return ctl4_orig; +} + +static void test_lctl4(long ctl4_orig) +{ + asm volatile( + "lctlg 4,4,%[ctl4_orig]" + : + : [ctl4_orig] "S" (ctl4_orig) + : + ); +} + +static void test_stpx(long ignore) +{ + unsigned int prefix; + + asm volatile( + "stpx %[prefix]" + : [prefix] "=Q" (prefix) + ); +} + +static void test_stfl(long ignore) +{ + asm volatile( + "stfl 0" : : : "memory" + ); +} + +static void test_epsw(long ignore) +{ + long r1, r2; + + asm volatile( + "epsw %[r1], %[r2]" + : [r1] "=d" (r1), [r2] "=d" (r2) + : + : + ); +} + +static void test_illegal(long ignore) +{ + expect_pgm_int(); + asm volatile( + ".word 0" + : + : + : + ); + clear_pgm_int(); +} + +static long setup_servc(long arg) +{ + memset(pagebuf, 0, PAGE_SIZE); + return arg; +} + +static void test_servc(long ignore) +{ + SCCB *sccb = (SCCB *) pagebuf; + + sccb->h.length = 8; + servc(0, (unsigned long) sccb); +} + +static void test_stsi(long fc) +{ + stsi(pagebuf, fc, 2, 2); +} + +struct test { + const char *name; + /* + * When non-null, will be called once before running the test loop. + * Its return value will be given as argument to testfunc. + */ + long (*setupfunc)(long arg); + void (*testfunc)(long arg); + long arg; + long iters; +} const exittime_tests[] = { + {"nop", NULL, test_nop, 0, 200000 }, + {"sigp sense running(0)", NULL, test_sigp_sense_running, 0, 20000 }, + {"sigp sense running(1)", NULL, test_sigp_sense_running, 1, 20000 }, + {"diag9c(self)", setup_get_this_cpuaddr, test_diag9c, 0, 2000 }, + {"diag9c(0)", NULL, test_diag9c, 0, 2000 }, + {"diag9c(1)", NULL, test_diag9c, 1, 2000 }, + {"diag44", NULL, test_diag44, 0, 2000 }, + {"stnsm", NULL, test_stnsm, 0, 200000 }, + {"stosm", NULL, test_stosm, 0, 200000 }, + {"ssm", setup_ssm, test_ssm, 0, 200000 }, + {"lctl4", setup_lctl4, test_lctl4, 0, 20000 }, + {"stpx", NULL, test_stpx, 0, 2000 }, + {"stfl", NULL, test_stfl, 0, 2000 }, + {"epsw", NULL, test_epsw, 0, 20000 }, + {"illegal", NULL, test_illegal, 0, 2000 }, + {"servc", setup_servc, test_servc, 0, 2000 }, + {"stsi122", NULL, test_stsi, 1, 200 }, + {"stsi222", NULL, test_stsi, 2, 200 }, + {"stsi322", NULL, test_stsi, 3, 200 }, +}; + +static uint64_t tod_to_us(uint64_t tod) +{ + return tod >> STCK_SHIFT_US; +} + +int main(void) +{ + int i, j, k, testfunc_arg; + const int outer_iters = 100; + struct test const *current_test; + uint64_t start, end, elapsed, worst, best, total; + + report_prefix_push("exittime"); + report_pass("reporting total/best/worst of %d outer iterations", outer_iters); + + for (i = 0; i < ARRAY_SIZE(exittime_tests); i++) { + current_test = &exittime_tests[i]; + total = 0; + worst = 0; + best = -1; + report_prefix_pushf("%s", current_test->name); + + testfunc_arg = current_test->arg; + if (current_test->setupfunc) + testfunc_arg = current_test->setupfunc(testfunc_arg); + + for (j = 0; j < outer_iters; j++) { + start = get_clock_fast(); + for (k = 0; k < current_test->iters; k++) + current_test->testfunc(testfunc_arg); + end = get_clock_fast(); + elapsed = end - start; + best = MIN(best, elapsed); + worst = MAX(worst, elapsed); + total += elapsed; + } + report_pass("iters/total/best/worst %lu/%lu/%lu/%lu us", current_test->iters, tod_to_us(total), tod_to_us(best), tod_to_us(worst)); + report_prefix_pop(); + } + + report_prefix_pop(); + return report_summary(); +} diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg index f7b1fc3dbca1..c11d1d987c82 100644 --- a/s390x/unittests.cfg +++ b/s390x/unittests.cfg @@ -185,3 +185,7 @@ groups = migration [migration-skey] file = migration-skey.elf groups = migration + +[exittime] +file = exittime.elf +smp = 2 -- 2.36.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [kvm-unit-tests PATCH v2 2/2] s390x: add exittime tests 2022-09-01 15:09 ` [kvm-unit-tests PATCH v2 2/2] s390x: add exittime tests Nico Boehr @ 2022-10-06 11:15 ` Claudio Imbrenda 0 siblings, 0 replies; 7+ messages in thread From: Claudio Imbrenda @ 2022-10-06 11:15 UTC (permalink / raw) To: Nico Boehr; +Cc: kvm, frankja, thuth On Thu, 1 Sep 2022 17:09:56 +0200 Nico Boehr <nrb@linux.ibm.com> wrote: > Add a test to measure the execution time of several instructions. This > can be helpful in finding performance regressions in hypervisor code. > > All tests are currently reported as PASS, since the baseline for their > execution time depends on the respective environment and since needs to > be determined on a case-by-case basis. > > Signed-off-by: Nico Boehr <nrb@linux.ibm.com> > --- > s390x/Makefile | 1 + > s390x/exittime.c | 255 ++++++++++++++++++++++++++++++++++++++++++++ > s390x/unittests.cfg | 4 + > 3 files changed, 260 insertions(+) > create mode 100644 s390x/exittime.c > > diff --git a/s390x/Makefile b/s390x/Makefile > index efd5e0c13102..5dcac244767f 100644 > --- a/s390x/Makefile > +++ b/s390x/Makefile > @@ -34,6 +34,7 @@ tests += $(TEST_DIR)/migration.elf > tests += $(TEST_DIR)/pv-attest.elf > tests += $(TEST_DIR)/migration-cmm.elf > tests += $(TEST_DIR)/migration-skey.elf > +tests += $(TEST_DIR)/exittime.elf > > pv-tests += $(TEST_DIR)/pv-diags.elf > > diff --git a/s390x/exittime.c b/s390x/exittime.c > new file mode 100644 > index 000000000000..543c82ff3906 > --- /dev/null > +++ b/s390x/exittime.c > @@ -0,0 +1,255 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Measure run time of various instructions. Can be used to find runtime > + * regressions of instructions which cause exits. > + * > + * Copyright IBM Corp. 2022 > + * > + * Authors: > + * Nico Boehr <nrb@linux.ibm.com> > + */ > +#include <libcflat.h> > +#include <smp.h> > +#include <sclp.h> > +#include <asm/time.h> > +#include <asm/sigp.h> > +#include <asm/interrupt.h> > +#include <asm/page.h> > + > +char pagebuf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); > + > +static void test_sigp_sense_running(long destcpu) > +{ > + smp_sigp(destcpu, SIGP_SENSE_RUNNING, 0, NULL); > +} > + > +static void test_nop(long ignore) > +{ > + /* nops don't trap into the hypervisor, so let's test them for reference */ > + asm volatile("nop" : : : "memory"); > +} > + > +static void test_diag9c(long destcpu) > +{ > + asm volatile("diag %[destcpu],0,0x9c" > + : > + : [destcpu] "d" (destcpu) > + : here you leave some unused : > + ); > +} > + > +static long setup_get_this_cpuaddr(long ignore) > +{ > + return stap(); > +} > + > +static void test_diag44(long ignore) > +{ > + asm volatile("diag 0,0,0x44"); > +} > + > +static void test_stnsm(long ignore) > +{ > + int out; > + > + asm volatile( > + "stnsm %[out],0xff" > + : [out] "=Q" (out) > + : here too, but you are using only 2 > + ); > +} > + > +static void test_stosm(long ignore) > +{ > + int out; > + > + asm volatile( > + "stosm %[out],0" > + : [out] "=Q" (out) > + : > + ); > +} > + > +static long setup_ssm(long ignore) > +{ > + long system_mask = 0; > + > + asm volatile( > + "stosm %[system_mask],0" > + : [system_mask] "=Q" (system_mask) > + : > + : > + ); > + > + return system_mask; > +} > + > +static void test_ssm(long old_system_mask) > +{ > + asm volatile( > + "ssm %[old_system_mask]" > + : > + : [old_system_mask] "Q" (old_system_mask) > + : > + ); > +} > + > +static long setup_lctl4(long ignore) > +{ > + long ctl4_orig = 0; > + > + asm volatile( > + "stctg 4,4,%[ctl4_orig]" > + : [ctl4_orig] "=S" (ctl4_orig) > + : > + : > + ); > + > + return ctl4_orig; > +} > + > +static void test_lctl4(long ctl4_orig) > +{ > + asm volatile( > + "lctlg 4,4,%[ctl4_orig]" > + : > + : [ctl4_orig] "S" (ctl4_orig) > + : > + ); > +} > + > +static void test_stpx(long ignore) > +{ > + unsigned int prefix; > + > + asm volatile( > + "stpx %[prefix]" > + : [prefix] "=Q" (prefix) here you are only using the : you actually need > + ); > +} > + > +static void test_stfl(long ignore) > +{ > + asm volatile( > + "stfl 0" : : : "memory" > + ); > +} > + > +static void test_epsw(long ignore) > +{ > + long r1, r2; > + > + asm volatile( > + "epsw %[r1], %[r2]" > + : [r1] "=d" (r1), [r2] "=d" (r2) > + : > + : > + ); > +} > + > +static void test_illegal(long ignore) > +{ > + expect_pgm_int(); > + asm volatile( > + ".word 0" > + : > + : > + : here none are needed > + ); > + clear_pgm_int(); > +} decide how you want to do for the : and then do it uniformly. either you always put all three : (except when none are needed), or you always only put as many as needed, without empty trailing ones. > + > +static long setup_servc(long arg) > +{ > + memset(pagebuf, 0, PAGE_SIZE); > + return arg; > +} > + > +static void test_servc(long ignore) > +{ > + SCCB *sccb = (SCCB *) pagebuf; > + > + sccb->h.length = 8; > + servc(0, (unsigned long) sccb); > +} > + > +static void test_stsi(long fc) > +{ > + stsi(pagebuf, fc, 2, 2); > +} > + > +struct test { > + const char *name; > + /* > + * When non-null, will be called once before running the test loop. > + * Its return value will be given as argument to testfunc. > + */ > + long (*setupfunc)(long arg); > + void (*testfunc)(long arg); > + long arg; > + long iters; > +} const exittime_tests[] = { > + {"nop", NULL, test_nop, 0, 200000 }, > + {"sigp sense running(0)", NULL, test_sigp_sense_running, 0, 20000 }, > + {"sigp sense running(1)", NULL, test_sigp_sense_running, 1, 20000 }, > + {"diag9c(self)", setup_get_this_cpuaddr, test_diag9c, 0, 2000 }, > + {"diag9c(0)", NULL, test_diag9c, 0, 2000 }, > + {"diag9c(1)", NULL, test_diag9c, 1, 2000 }, > + {"diag44", NULL, test_diag44, 0, 2000 }, > + {"stnsm", NULL, test_stnsm, 0, 200000 }, > + {"stosm", NULL, test_stosm, 0, 200000 }, > + {"ssm", setup_ssm, test_ssm, 0, 200000 }, > + {"lctl4", setup_lctl4, test_lctl4, 0, 20000 }, > + {"stpx", NULL, test_stpx, 0, 2000 }, > + {"stfl", NULL, test_stfl, 0, 2000 }, > + {"epsw", NULL, test_epsw, 0, 20000 }, > + {"illegal", NULL, test_illegal, 0, 2000 }, > + {"servc", setup_servc, test_servc, 0, 2000 }, > + {"stsi122", NULL, test_stsi, 1, 200 }, > + {"stsi222", NULL, test_stsi, 2, 200 }, > + {"stsi322", NULL, test_stsi, 3, 200 }, > +}; > + > +static uint64_t tod_to_us(uint64_t tod) > +{ > + return tod >> STCK_SHIFT_US; > +} > + > +int main(void) > +{ > + int i, j, k, testfunc_arg; > + const int outer_iters = 100; > + struct test const *current_test; > + uint64_t start, end, elapsed, worst, best, total; > + > + report_prefix_push("exittime"); > + report_pass("reporting total/best/worst of %d outer iterations", outer_iters); > + > + for (i = 0; i < ARRAY_SIZE(exittime_tests); i++) { > + current_test = &exittime_tests[i]; > + total = 0; > + worst = 0; > + best = -1; > + report_prefix_pushf("%s", current_test->name); > + > + testfunc_arg = current_test->arg; > + if (current_test->setupfunc) > + testfunc_arg = current_test->setupfunc(testfunc_arg); > + > + for (j = 0; j < outer_iters; j++) { > + start = get_clock_fast(); > + for (k = 0; k < current_test->iters; k++) > + current_test->testfunc(testfunc_arg); > + end = get_clock_fast(); > + elapsed = end - start; > + best = MIN(best, elapsed); > + worst = MAX(worst, elapsed); > + total += elapsed; > + } > + report_pass("iters/total/best/worst %lu/%lu/%lu/%lu us", current_test->iters, tod_to_us(total), tod_to_us(best), tod_to_us(worst)); perhaps it would not be a bad idea to also print the average and the standard deviation (σ) > + report_prefix_pop(); > + } > + > + report_prefix_pop(); > + return report_summary(); > +} > diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg > index f7b1fc3dbca1..c11d1d987c82 100644 > --- a/s390x/unittests.cfg > +++ b/s390x/unittests.cfg > @@ -185,3 +185,7 @@ groups = migration > [migration-skey] > file = migration-skey.elf > groups = migration > + > +[exittime] > +file = exittime.elf > +smp = 2 ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test 2022-09-01 15:09 [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test Nico Boehr 2022-09-01 15:09 ` [kvm-unit-tests PATCH v2 1/2] lib/s390x: time: add wrapper for stckf Nico Boehr 2022-09-01 15:09 ` [kvm-unit-tests PATCH v2 2/2] s390x: add exittime tests Nico Boehr @ 2022-10-06 11:18 ` Claudio Imbrenda 2022-10-11 11:26 ` Nico Boehr 2 siblings, 1 reply; 7+ messages in thread From: Claudio Imbrenda @ 2022-10-06 11:18 UTC (permalink / raw) To: Nico Boehr; +Cc: kvm, frankja, thuth On Thu, 1 Sep 2022 17:09:54 +0200 Nico Boehr <nrb@linux.ibm.com> wrote: > v1->v2: > --- > * add missing cc clobber, fix constraints for get_clock_us() (thanks > Thomas) > * avoid array and use pointer to const char* (thanks Thomas) > * add comment why testing nop makes sense (thanks Thomas) > * rework constraints and clobbers (thanks Thomas) > > Sometimes, it is useful to measure the exit time of certain instructions > to e.g. identify performance regressions in instructions emulated by the > hypervisor. > > This series adds a test which executes some instructions and measures > their execution time. Since their execution time depends a lot on the > environment at hand, all tests are reported as PASS currently. > > The point of this series is not so much the instructions which have been > chosen here (but your ideas are welcome), but rather the general > question whether it makes sense to have a test like this in > kvm-unit-tests. perhaps it makes sense to merge this patch series with your other one, "s390x: Add migration test for guest TOD clock" they both concern timing and reshuffling around and/or fixing timing functions > > Nico Boehr (2): > lib/s390x: time: add wrapper for stckf > s390x: add exittime tests > > lib/s390x/asm/time.h | 11 +- > s390x/Makefile | 1 + > s390x/exittime.c | 255 +++++++++++++++++++++++++++++++++++++++++++ > s390x/unittests.cfg | 4 + > 4 files changed, 270 insertions(+), 1 deletion(-) > create mode 100644 s390x/exittime.c > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test 2022-10-06 11:18 ` [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test Claudio Imbrenda @ 2022-10-11 11:26 ` Nico Boehr 0 siblings, 0 replies; 7+ messages in thread From: Nico Boehr @ 2022-10-11 11:26 UTC (permalink / raw) To: Claudio Imbrenda; +Cc: kvm, frankja, thuth Claudio, Quoting Claudio Imbrenda (2022-10-06 13:18:56) > perhaps it makes sense to merge this patch series with your other one, > "s390x: Add migration test for guest TOD clock" > > they both concern timing and reshuffling around and/or fixing timing > functions Since the TOD migration test is useful for regression testing my PV clock fix[1], I would like to have this in ASAP. The exittime test, though, can wait for a bit. If it's OK for you, I would like to keep these things seperate and rather (re-)base the exittime test on the TOD migration test. [1] https://lore.kernel.org/all/20221005163258.117232-1-nrb@linux.ibm.com/ ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-10-11 11:26 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-09-01 15:09 [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test Nico Boehr 2022-09-01 15:09 ` [kvm-unit-tests PATCH v2 1/2] lib/s390x: time: add wrapper for stckf Nico Boehr 2022-10-06 11:16 ` Claudio Imbrenda 2022-09-01 15:09 ` [kvm-unit-tests PATCH v2 2/2] s390x: add exittime tests Nico Boehr 2022-10-06 11:15 ` Claudio Imbrenda 2022-10-06 11:18 ` [kvm-unit-tests PATCH v2 0/2] s390x: Add exit time test Claudio Imbrenda 2022-10-11 11:26 ` Nico Boehr
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