Date: Tue, 21 Apr 2026 14:11:58 +0000 From: Mitchell Horne <mhorne@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Cc: Ali Mashtizadeh <ali@mashtizadeh.com> Subject: git: fd45987f1f66 - main - hwpmc: Implement IBS process sampling Message-ID: <69e785ae.24088.6767c652@gitrepo.freebsd.org>
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The branch main has been updated by mhorne: URL: https://cgit.FreeBSD.org/src/commit/?id=fd45987f1f66fe01b0cecede9e90c8aea5cae87e commit fd45987f1f66fe01b0cecede9e90c8aea5cae87e Author: Ali Mashtizadeh <ali@mashtizadeh.com> AuthorDate: 2026-04-07 23:30:51 +0000 Commit: Mitchell Horne <mhorne@FreeBSD.org> CommitDate: 2026-04-21 14:11:41 +0000 hwpmc: Implement IBS process sampling This change enables process-wide sampling to work with IBS by ensuring that read/write only gets or sets the current counter. Reviewed by: mhorne Sponsored by: Netflix Pull Request: https://github.com/freebsd/freebsd-src/pull/2131 --- sys/dev/hwpmc/hwpmc_ibs.c | 28 +++++++++++++++++++++++++--- sys/dev/hwpmc/hwpmc_ibs.h | 8 ++++++++ 2 files changed, 33 insertions(+), 3 deletions(-) diff --git a/sys/dev/hwpmc/hwpmc_ibs.c b/sys/dev/hwpmc/hwpmc_ibs.c index a230288f157e..574df12093f8 100644 --- a/sys/dev/hwpmc/hwpmc_ibs.c +++ b/sys/dev/hwpmc/hwpmc_ibs.c @@ -82,13 +82,13 @@ ibs_read_pmc(int cpu, int ri, struct pmc *pm, pmc_value_t *v) KASSERT(ibs_pcpu[cpu], ("[ibs,%d] null per-cpu, cpu %d", __LINE__, cpu)); - /* read the IBS ctl */ + /* read the IBS count */ switch (ri) { case IBS_PMC_FETCH: - *v = rdmsr(IBS_FETCH_CTL); + *v = IBS_FETCH_CTL_TO_COUNT(rdmsr(IBS_FETCH_CTL)); break; case IBS_PMC_OP: - *v = rdmsr(IBS_OP_CTL); + *v = IBS_OP_CTL_TO_COUNT(rdmsr(IBS_OP_CTL)); break; } @@ -103,12 +103,31 @@ ibs_read_pmc(int cpu, int ri, struct pmc *pm, pmc_value_t *v) static int ibs_write_pmc(int cpu, int ri, struct pmc *pm, pmc_value_t v) { + pmc_value_t m; KASSERT(cpu >= 0 && cpu < pmc_cpu_max(), ("[ibs,%d] illegal CPU value %d", __LINE__, cpu)); KASSERT(ri >= 0 && ri < IBS_NPMCS, ("[ibs,%d] illegal row-index %d", __LINE__, ri)); + /* write the IBS count */ + switch (ri) { + case IBS_PMC_FETCH: + m = rdmsr(IBS_FETCH_CTL) & ~IBS_FETCH_CTL_CURCNTMASK; + /* Setting a count greater than interval is undefined. */ + if (IBS_FETCH_CTL_TO_INTERVAL(m) > v) + m |= IBS_FETCH_COUNT_TO_CTL(v); + wrmsr(IBS_FETCH_CTL, m); + break; + case IBS_PMC_OP: + m = rdmsr(IBS_OP_CTL) & ~IBS_OP_CTL_CURCNTMASK; + /* Setting a count greater than interval is undefined */ + if (IBS_OP_CTL_TO_INTERVAL(m) > v) + m |= IBS_OP_COUNT_TO_CTL(v); + wrmsr(IBS_OP_CTL, m); + break; + } + PMCDBG3(MDP, WRI, 1, "ibs-write cpu=%d ri=%d v=%jx", cpu, ri, v); return (0); @@ -177,6 +196,9 @@ ibs_allocate_pmc(int cpu __unused, int ri, struct pmc *pm, if ((caps & PMC_CAP_SYSTEM) == 0) return (EINVAL); + if (!PMC_IS_SAMPLING_MODE(a->pm_mode)) + return (EINVAL); + config = a->pm_md.pm_ibs.ibs_ctl; pm->pm_md.pm_ibs.ibs_ctl = config; diff --git a/sys/dev/hwpmc/hwpmc_ibs.h b/sys/dev/hwpmc/hwpmc_ibs.h index 1616a746ffef..4cb69503bd8b 100644 --- a/sys/dev/hwpmc/hwpmc_ibs.h +++ b/sys/dev/hwpmc/hwpmc_ibs.h @@ -92,9 +92,13 @@ #define IBS_FETCH_CTL_VALID (1ULL << 49) /* Valid */ #define IBS_FETCH_CTL_ENABLE (1ULL << 48) /* Enable */ #define IBS_FETCH_CTL_MAXCNTMASK 0x0000FFFFULL +#define IBS_FETCH_CTL_CURCNTMASK 0xFFFF0000ULL #define IBS_FETCH_INTERVAL_TO_CTL(_c) (((_c) >> 4) & 0x0000FFFF) +#define IBS_FETCH_CTL_TO_INTERVAL(_c) (((_c) & IBS_FETCH_CTL_MAXCNTMASK) << 4) #define IBS_FETCH_CTL_TO_LAT(_c) (((_c) >> 32) & 0x0000FFFF) +#define IBS_FETCH_COUNT_TO_CTL(_c) (((_c) << 12) & IBS_FETCH_CTL_CURCNTMASK) +#define IBS_FETCH_CTL_TO_COUNT(_c) (((_c) & IBS_FETCH_CTL_CURCNTMASK) >> 12) #define IBS_FETCH_LINADDR 0xC0011031 /* Fetch Linear Address */ #define IBS_FETCH_PHYSADDR 0xC0011032 /* Fetch Physical Address */ @@ -113,9 +117,13 @@ #define IBS_OP_CTL_ENABLE (1ULL << 17) /* Enable */ #define IBS_OP_CTL_L3MISSONLY (1ULL << 16) /* L3 Miss Filtering */ #define IBS_OP_CTL_MAXCNTMASK 0x07F0FFFFULL +#define IBS_OP_CTL_CURCNTMASK 0x07FFFFFF00000000ULL #define IBS_OP_CTL_LDLAT_TO_CTL(_c) ((((ldlat) >> 7) - 1) << 59) #define IBS_OP_INTERVAL_TO_CTL(_c) ((((_c) >> 4) & 0x0000FFFFULL) | ((_c) & 0x07F00000)) +#define IBS_OP_CTL_TO_INTERVAL(_c) ((((_c) & 0x0000FFFFULL) << 4) | ((_c) & 0x07F00000)) +#define IBS_OP_COUNT_TO_CTL(_c) (((_c) << 32) & IBS_OP_CTL_CURCNTMASK) +#define IBS_OP_CTL_TO_COUNT(_c) (((_c) & IBS_OP_CTL_CURCNTMASK) >> 32) #define IBS_OP_RIP 0xC0011034 /* IBS Op RIP */ #define IBS_OP_DATA 0xC0011035 /* IBS Op Data */home | help
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