Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
#include <stdlib.h>
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#include <signal.h>
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#include <unistd.h>
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#include <linux/compiler.h>
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#include "../tests.h"
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typedef struct _buf {
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char data1;
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char reserved[55];
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char data2;
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} buf __attribute__((aligned(64)));
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/* volatile to try to avoid the compiler seeing reserved as unused. */
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static volatile buf workload_datasym_buf1 = {
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/* to have this in the data section */
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.reserved[0] = 1,
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};
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static volatile sig_atomic_t done;
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static void sighandler(int sig __maybe_unused)
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{
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done = 1;
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}
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static int datasym(int argc, const char **argv)
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{
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int sec = 1;
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if (argc > 0)
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sec = atoi(argv[0]);
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signal(SIGINT, sighandler);
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signal(SIGALRM, sighandler);
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alarm(sec);
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while (!done) {
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workload_datasym_buf1.data1++;
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if (workload_datasym_buf1.data1 == 123) {
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/*
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* Add some 'noise' in the loop to work around errata
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* 1694299 on Arm N1.
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*
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* Bias exists in SPE sampling which can cause the load
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* and store instructions to be skipped entirely. This
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* comes and goes randomly depending on the offset the
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* linker places the datasym loop at in the Perf binary.
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* With an extra branch in the middle of the loop that
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* isn't always taken, the instruction stream is no
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* longer a continuous repeating pattern that interacts
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* badly with the bias.
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*/
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workload_datasym_buf1.data1++;
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}
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workload_datasym_buf1.data2 += workload_datasym_buf1.data1;
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}
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return 0;
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}
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DEFINE_WORKLOAD(datasym);
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