svn commit: r294046 - in stable/10: lib/libpmc sys/dev/hwpmc sys/sys usr.sbin/pmcstat
Jonathan T. Looney
jtl at FreeBSD.org
Thu Jan 14 22:02:23 UTC 2016
Author: jtl
Date: Thu Jan 14 22:02:21 2016
New Revision: 294046
URL: https://svnweb.freebsd.org/changeset/base/294046
Log:
MFC r290811:
Fix hwpmc "stalled" behavior
Currently, there is a single pm_stalled flag that tracks whether a
performance monitor was "stalled" due to insufficent ring buffer
space for samples. However, because the same performance monitor
can run on multiple processes or threads at the same time, a single
pm_stalled flag that impacts them all seems insufficient.
In particular, you can hit corner cases where the code fails to stop
performance monitors during a context switch out, because it thinks
the performance monitor is already stopped. However, in reality,
it may be that only the monitor running on a different CPU was stalled.
This patch attempts to fix that behavior by tracking on a per-CPU basis
whether a PM desires to run and whether it is "stalled". This lets the
code make better decisions about when to stop PMs and when to try to
restart them. Ideally, we should avoid the case where the code fails
to stop a PM during a context switch out.
MFC r290813:
Optimizations to the way hwpmc gathers user callchains
Changes to the code to gather user stacks:
* Delay setting pmc_cpumask until we actually have the stack.
* When recording user stack traces, only walk the portion of the ring
that should have samples for us.
MFC r290929:
Change the driver stats to what they really are: unsigned values.
When pmcstat exits after some samples were dropped, give the user an
idea of how many were lost. (Granted, these are global numbers, but
they may still help quantify the scope of the loss.)
MFC r290930:
Improve accuracy of PMC sampling frequency
The code tracks a counter which is the number of events until the next
sample. On context switch in, it loads the saved counter. On context
switch out, it tries to calculate a new saved counter.
Problems:
1. The saved counter was shared by all threads in a process. However, this
means that all threads would be initially loaded with the same saved
counter. However, that could result in sampling more often than once every
X number of events.
2. The calculation to determine a new saved counter was backwards. It
added when it should have subtracted, and subtracted when it should have
added. Assume a single-threaded process with a reload count of 1000
events. Assuming the counter on context switch in was 100 and the counter
on context switch out was 50 (meaning the thread has "consumed" 50 more
events), the code would calculate a new saved counter of 150 (instead of
the proper 50).
Fix:
1. As soon as the saved counter is used to initialize a monitor for a
thread on context switch in, set the saved counter to the reload count.
That way, subsequent threads to use the saved counter will get the full
reload count, assuring we sample at least once every X number of events
(across all threads).
2. Change the calculation of the saved counter. Due to the change to the
saved counter in #1, we simply need to add (modulo the reload count) the
remaining counter time we retrieve from the CPU when a thread is context
switched out.
MFC r291016:
Support a wider history counter in pmcstat(8) gmon output
pmcstat(8) contains an option to output sampling data in a gmon format
compatible with gprof(1). Currently, it uses the default histcounter,
which is an (unsigned short). With large sets of sampling data, it
is possible to overflow the maximum value provided by an (unsigned
short).
This change adds the -e argument to pmcstat. If -e and -g are both
specified, pmcstat will use a histcounter type of uint64_t.
MFC r291017:
Fix the date on the pmcstat(8) man page from r291016.
Modified:
stable/10/lib/libpmc/pmc.h
stable/10/sys/dev/hwpmc/hwpmc_mod.c
stable/10/sys/sys/pmc.h
stable/10/usr.sbin/pmcstat/pmcpl_gprof.c
stable/10/usr.sbin/pmcstat/pmcstat.8
stable/10/usr.sbin/pmcstat/pmcstat.c
stable/10/usr.sbin/pmcstat/pmcstat.h
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/lib/libpmc/pmc.h
==============================================================================
--- stable/10/lib/libpmc/pmc.h Thu Jan 14 21:59:43 2016 (r294045)
+++ stable/10/lib/libpmc/pmc.h Thu Jan 14 22:02:21 2016 (r294046)
@@ -36,14 +36,15 @@
* Driver statistics.
*/
struct pmc_driverstats {
- int pm_intr_ignored; /* #interrupts ignored */
- int pm_intr_processed; /* #interrupts processed */
- int pm_intr_bufferfull; /* #interrupts with ENOSPC */
- int pm_syscalls; /* #syscalls */
- int pm_syscall_errors; /* #syscalls with errors */
- int pm_buffer_requests; /* #buffer requests */
- int pm_buffer_requests_failed; /* #failed buffer requests */
- int pm_log_sweeps; /* #sample buffer processing passes */
+ unsigned int pm_intr_ignored; /* #interrupts ignored */
+ unsigned int pm_intr_processed; /* #interrupts processed */
+ unsigned int pm_intr_bufferfull; /* #interrupts with ENOSPC */
+ unsigned int pm_syscalls; /* #syscalls */
+ unsigned int pm_syscall_errors; /* #syscalls with errors */
+ unsigned int pm_buffer_requests; /* #buffer requests */
+ unsigned int pm_buffer_requests_failed; /* #failed buffer requests */
+ unsigned int pm_log_sweeps; /* #sample buffer processing
+ passes */
};
/*
Modified: stable/10/sys/dev/hwpmc/hwpmc_mod.c
==============================================================================
--- stable/10/sys/dev/hwpmc/hwpmc_mod.c Thu Jan 14 21:59:43 2016 (r294045)
+++ stable/10/sys/dev/hwpmc/hwpmc_mod.c Thu Jan 14 22:02:21 2016 (r294046)
@@ -1287,8 +1287,16 @@ pmc_process_csw_in(struct thread *td)
*/
if (PMC_TO_MODE(pm) == PMC_MODE_TS) {
mtx_pool_lock_spin(pmc_mtxpool, pm);
+
+ /*
+ * Use the saved value calculated after the most recent
+ * thread switch out to start this counter. Reset
+ * the saved count in case another thread from this
+ * process switches in before any threads switch out.
+ */
newvalue = PMC_PCPU_SAVED(cpu,ri) =
pp->pp_pmcs[ri].pp_pmcval;
+ pp->pp_pmcs[ri].pp_pmcval = pm->pm_sc.pm_reloadcount;
mtx_pool_unlock_spin(pmc_mtxpool, pm);
} else {
KASSERT(PMC_TO_MODE(pm) == PMC_MODE_TC,
@@ -1303,6 +1311,15 @@ pmc_process_csw_in(struct thread *td)
PMCDBG3(CSW,SWI,1,"cpu=%d ri=%d new=%jd", cpu, ri, newvalue);
pcd->pcd_write_pmc(cpu, adjri, newvalue);
+
+ /* If a sampling mode PMC, reset stalled state. */
+ if (PMC_TO_MODE(pm) == PMC_MODE_TS)
+ CPU_CLR_ATOMIC(cpu, &pm->pm_stalled);
+
+ /* Indicate that we desire this to run. */
+ CPU_SET_ATOMIC(cpu, &pm->pm_cpustate);
+
+ /* Start the PMC. */
pcd->pcd_start_pmc(cpu, adjri);
}
@@ -1397,8 +1414,14 @@ pmc_process_csw_out(struct thread *td)
("[pmc,%d] ri mismatch pmc(%d) ri(%d)",
__LINE__, PMC_TO_ROWINDEX(pm), ri));
- /* Stop hardware if not already stopped */
- if (pm->pm_stalled == 0)
+ /*
+ * Change desired state, and then stop if not stalled.
+ * This two-step dance should avoid race conditions where
+ * an interrupt re-enables the PMC after this code has
+ * already checked the pm_stalled flag.
+ */
+ CPU_CLR_ATOMIC(cpu, &pm->pm_cpustate);
+ if (!CPU_ISSET(cpu, &pm->pm_stalled))
pcd->pcd_stop_pmc(cpu, adjri);
/* reduce this PMC's runcount */
@@ -1421,31 +1444,43 @@ pmc_process_csw_out(struct thread *td)
pcd->pcd_read_pmc(cpu, adjri, &newvalue);
- tmp = newvalue - PMC_PCPU_SAVED(cpu,ri);
-
- PMCDBG3(CSW,SWO,1,"cpu=%d ri=%d tmp=%jd", cpu, ri,
- tmp);
-
if (mode == PMC_MODE_TS) {
+ PMCDBG3(CSW,SWO,1,"cpu=%d ri=%d tmp=%jd (samp)",
+ cpu, ri, PMC_PCPU_SAVED(cpu,ri) - newvalue);
/*
* For sampling process-virtual PMCs,
- * we expect the count to be
- * decreasing as the 'value'
- * programmed into the PMC is the
- * number of events to be seen till
- * the next sampling interrupt.
+ * newvalue is the number of events to be seen
+ * until the next sampling interrupt.
+ * We can just add the events left from this
+ * invocation to the counter, then adjust
+ * in case we overflow our range.
+ *
+ * (Recall that we reload the counter every
+ * time we use it.)
*/
- if (tmp < 0)
- tmp += pm->pm_sc.pm_reloadcount;
mtx_pool_lock_spin(pmc_mtxpool, pm);
- pp->pp_pmcs[ri].pp_pmcval -= tmp;
- if ((int64_t) pp->pp_pmcs[ri].pp_pmcval <= 0)
- pp->pp_pmcs[ri].pp_pmcval +=
+
+ pp->pp_pmcs[ri].pp_pmcval += newvalue;
+ if (pp->pp_pmcs[ri].pp_pmcval >
+ pm->pm_sc.pm_reloadcount)
+ pp->pp_pmcs[ri].pp_pmcval -=
pm->pm_sc.pm_reloadcount;
+ KASSERT(pp->pp_pmcs[ri].pp_pmcval > 0 &&
+ pp->pp_pmcs[ri].pp_pmcval <=
+ pm->pm_sc.pm_reloadcount,
+ ("[pmc,%d] pp_pmcval outside of expected "
+ "range cpu=%d ri=%d pp_pmcval=%jx "
+ "pm_reloadcount=%jx", __LINE__, cpu, ri,
+ pp->pp_pmcs[ri].pp_pmcval,
+ pm->pm_sc.pm_reloadcount));
mtx_pool_unlock_spin(pmc_mtxpool, pm);
} else {
+ tmp = newvalue - PMC_PCPU_SAVED(cpu,ri);
+
+ PMCDBG3(CSW,SWO,1,"cpu=%d ri=%d tmp=%jd (count)",
+ cpu, ri, tmp);
/*
* For counting process-virtual PMCs,
@@ -2263,8 +2298,9 @@ pmc_release_pmc_descriptor(struct pmc *p
pmc_select_cpu(cpu);
/* switch off non-stalled CPUs */
+ CPU_CLR_ATOMIC(cpu, &pm->pm_cpustate);
if (pm->pm_state == PMC_STATE_RUNNING &&
- pm->pm_stalled == 0) {
+ !CPU_ISSET(cpu, &pm->pm_stalled)) {
phw = pmc_pcpu[cpu]->pc_hwpmcs[ri];
@@ -2678,8 +2714,15 @@ pmc_start(struct pmc *pm)
if ((error = pcd->pcd_write_pmc(cpu, adjri,
PMC_IS_SAMPLING_MODE(mode) ?
pm->pm_sc.pm_reloadcount :
- pm->pm_sc.pm_initial)) == 0)
+ pm->pm_sc.pm_initial)) == 0) {
+ /* If a sampling mode PMC, reset stalled state. */
+ if (PMC_IS_SAMPLING_MODE(mode))
+ CPU_CLR_ATOMIC(cpu, &pm->pm_stalled);
+
+ /* Indicate that we desire this to run. Start it. */
+ CPU_SET_ATOMIC(cpu, &pm->pm_cpustate);
error = pcd->pcd_start_pmc(cpu, adjri);
+ }
critical_exit();
pmc_restore_cpu_binding(&pb);
@@ -2741,6 +2784,7 @@ pmc_stop(struct pmc *pm)
ri = PMC_TO_ROWINDEX(pm);
pcd = pmc_ri_to_classdep(md, ri, &adjri);
+ CPU_CLR_ATOMIC(cpu, &pm->pm_cpustate);
critical_enter();
if ((error = pcd->pcd_stop_pmc(cpu, adjri)) == 0)
error = pcd->pcd_read_pmc(cpu, adjri, &pm->pm_sc.pm_initial);
@@ -4049,12 +4093,13 @@ pmc_process_interrupt(int cpu, int ring,
ps = psb->ps_write;
if (ps->ps_nsamples) { /* in use, reader hasn't caught up */
- pm->pm_stalled = 1;
+ CPU_SET_ATOMIC(cpu, &pm->pm_stalled);
atomic_add_int(&pmc_stats.pm_intr_bufferfull, 1);
PMCDBG6(SAM,INT,1,"(spc) cpu=%d pm=%p tf=%p um=%d wr=%d rd=%d",
cpu, pm, (void *) tf, inuserspace,
(int) (psb->ps_write - psb->ps_samples),
(int) (psb->ps_read - psb->ps_samples));
+ callchaindepth = 1;
error = ENOMEM;
goto done;
}
@@ -4112,7 +4157,8 @@ pmc_process_interrupt(int cpu, int ring,
done:
/* mark CPU as needing processing */
- CPU_SET_ATOMIC(cpu, &pmc_cpumask);
+ if (callchaindepth != PMC_SAMPLE_INUSE)
+ CPU_SET_ATOMIC(cpu, &pmc_cpumask);
return (error);
}
@@ -4126,10 +4172,9 @@ pmc_process_interrupt(int cpu, int ring,
static void
pmc_capture_user_callchain(int cpu, int ring, struct trapframe *tf)
{
- int i;
struct pmc *pm;
struct thread *td;
- struct pmc_sample *ps;
+ struct pmc_sample *ps, *ps_end;
struct pmc_samplebuffer *psb;
#ifdef INVARIANTS
int ncallchains;
@@ -4148,15 +4193,17 @@ pmc_capture_user_callchain(int cpu, int
/*
* Iterate through all deferred callchain requests.
+ * Walk from the current read pointer to the current
+ * write pointer.
*/
- ps = psb->ps_samples;
- for (i = 0; i < pmc_nsamples; i++, ps++) {
-
+ ps = psb->ps_read;
+ ps_end = psb->ps_write;
+ do {
if (ps->ps_nsamples != PMC_SAMPLE_INUSE)
- continue;
+ goto next;
if (ps->ps_td != td)
- continue;
+ goto next;
KASSERT(ps->ps_cpu == cpu,
("[pmc,%d] cpu mismatch ps_cpu=%d pcpu=%d", __LINE__,
@@ -4181,7 +4228,12 @@ pmc_capture_user_callchain(int cpu, int
#ifdef INVARIANTS
ncallchains++;
#endif
- }
+
+next:
+ /* increment the pointer, modulo sample ring size */
+ if (++ps == psb->ps_fence)
+ ps = psb->ps_samples;
+ } while (ps != ps_end);
KASSERT(ncallchains > 0,
("[pmc,%d] cpu %d didn't find a sample to collect", __LINE__,
@@ -4191,6 +4243,9 @@ pmc_capture_user_callchain(int cpu, int
("[pmc,%d] invalid td_pinned value", __LINE__));
sched_unpin(); /* Can migrate safely now. */
+ /* mark CPU as needing processing */
+ CPU_SET_ATOMIC(cpu, &pmc_cpumask);
+
return;
}
@@ -4304,10 +4359,11 @@ pmc_process_samples(int cpu, int ring)
if (pm == NULL || /* !cfg'ed */
pm->pm_state != PMC_STATE_RUNNING || /* !active */
!PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)) || /* !sampling */
- pm->pm_stalled == 0) /* !stalled */
+ !CPU_ISSET(cpu, &pm->pm_cpustate) || /* !desired */
+ !CPU_ISSET(cpu, &pm->pm_stalled)) /* !stalled */
continue;
- pm->pm_stalled = 0;
+ CPU_CLR_ATOMIC(cpu, &pm->pm_stalled);
(*pcd->pcd_start_pmc)(cpu, adjri);
}
}
@@ -4426,23 +4482,31 @@ pmc_process_exit(void *arg __unused, str
("[pmc,%d] pm %p != pp_pmcs[%d] %p",
__LINE__, pm, ri, pp->pp_pmcs[ri].pp_pmc));
- (void) pcd->pcd_stop_pmc(cpu, adjri);
-
KASSERT(pm->pm_runcount > 0,
("[pmc,%d] bad runcount ri %d rc %d",
__LINE__, ri, pm->pm_runcount));
- /* Stop hardware only if it is actually running */
- if (pm->pm_state == PMC_STATE_RUNNING &&
- pm->pm_stalled == 0) {
- pcd->pcd_read_pmc(cpu, adjri, &newvalue);
- tmp = newvalue -
- PMC_PCPU_SAVED(cpu,ri);
-
- mtx_pool_lock_spin(pmc_mtxpool, pm);
- pm->pm_gv.pm_savedvalue += tmp;
- pp->pp_pmcs[ri].pp_pmcval += tmp;
- mtx_pool_unlock_spin(pmc_mtxpool, pm);
+ /*
+ * Change desired state, and then stop if not
+ * stalled. This two-step dance should avoid
+ * race conditions where an interrupt re-enables
+ * the PMC after this code has already checked
+ * the pm_stalled flag.
+ */
+ if (CPU_ISSET(cpu, &pm->pm_cpustate)) {
+ CPU_CLR_ATOMIC(cpu, &pm->pm_cpustate);
+ if (!CPU_ISSET(cpu, &pm->pm_stalled)) {
+ (void) pcd->pcd_stop_pmc(cpu, adjri);
+ pcd->pcd_read_pmc(cpu, adjri,
+ &newvalue);
+ tmp = newvalue -
+ PMC_PCPU_SAVED(cpu,ri);
+
+ mtx_pool_lock_spin(pmc_mtxpool, pm);
+ pm->pm_gv.pm_savedvalue += tmp;
+ pp->pp_pmcs[ri].pp_pmcval += tmp;
+ mtx_pool_unlock_spin(pmc_mtxpool, pm);
+ }
}
atomic_subtract_rel_int(&pm->pm_runcount,1);
Modified: stable/10/sys/sys/pmc.h
==============================================================================
--- stable/10/sys/sys/pmc.h Thu Jan 14 21:59:43 2016 (r294045)
+++ stable/10/sys/sys/pmc.h Thu Jan 14 22:02:21 2016 (r294046)
@@ -534,14 +534,15 @@ struct pmc_op_configurelog {
*/
struct pmc_op_getdriverstats {
- int pm_intr_ignored; /* #interrupts ignored */
- int pm_intr_processed; /* #interrupts processed */
- int pm_intr_bufferfull; /* #interrupts with ENOSPC */
- int pm_syscalls; /* #syscalls */
- int pm_syscall_errors; /* #syscalls with errors */
- int pm_buffer_requests; /* #buffer requests */
- int pm_buffer_requests_failed; /* #failed buffer requests */
- int pm_log_sweeps; /* #sample buffer processing passes */
+ unsigned int pm_intr_ignored; /* #interrupts ignored */
+ unsigned int pm_intr_processed; /* #interrupts processed */
+ unsigned int pm_intr_bufferfull; /* #interrupts with ENOSPC */
+ unsigned int pm_syscalls; /* #syscalls */
+ unsigned int pm_syscall_errors; /* #syscalls with errors */
+ unsigned int pm_buffer_requests; /* #buffer requests */
+ unsigned int pm_buffer_requests_failed; /* #failed buffer requests */
+ unsigned int pm_log_sweeps; /* #sample buffer processing
+ passes */
};
/*
@@ -598,6 +599,7 @@ struct pmc_op_getdyneventinfo {
#include <sys/malloc.h>
#include <sys/sysctl.h>
+#include <sys/_cpuset.h>
#include <machine/frame.h>
@@ -713,7 +715,8 @@ struct pmc {
pmc_value_t pm_initial; /* counting PMC modes */
} pm_sc;
- uint32_t pm_stalled; /* marks stalled sampling PMCs */
+ volatile cpuset_t pm_stalled; /* marks stalled sampling PMCs */
+ volatile cpuset_t pm_cpustate; /* CPUs where PMC should be active */
uint32_t pm_caps; /* PMC capabilities */
enum pmc_event pm_event; /* event being measured */
uint32_t pm_flags; /* additional flags PMC_F_... */
Modified: stable/10/usr.sbin/pmcstat/pmcpl_gprof.c
==============================================================================
--- stable/10/usr.sbin/pmcstat/pmcpl_gprof.c Thu Jan 14 21:59:43 2016 (r294045)
+++ stable/10/usr.sbin/pmcstat/pmcpl_gprof.c Thu Jan 14 22:02:21 2016 (r294046)
@@ -74,6 +74,14 @@ __FBSDID("$FreeBSD$");
#include "pmcpl_callgraph.h"
#include "pmcpl_gprof.h"
+typedef uint64_t WIDEHISTCOUNTER;
+
+#define WIDEHISTCOUNTER_MAX UINT64_MAX
+#define HISTCOUNTER_MAX USHRT_MAX
+#define WIDEHISTCOUNTER_GMONTYPE ((int) 64)
+#define HISTCOUNTER_GMONTYPE ((int) 0)
+static int hc_sz=0;
+
/*
* struct pmcstat_gmonfile tracks a given 'gmon.out' file. These
* files are mmap()'ed in as needed.
@@ -126,11 +134,13 @@ pmcstat_gmon_create_file(struct pmcstat_
gm.lpc = image->pi_start;
gm.hpc = image->pi_end;
- gm.ncnt = (pgf->pgf_nbuckets * sizeof(HISTCOUNTER)) +
- sizeof(struct gmonhdr);
+ gm.ncnt = (pgf->pgf_nbuckets * hc_sz) + sizeof(struct gmonhdr);
gm.version = GMONVERSION;
gm.profrate = 0; /* use ticks */
- gm.histcounter_type = 0; /* compatibility with moncontrol() */
+ if (args.pa_flags & FLAG_DO_WIDE_GPROF_HC)
+ gm.histcounter_type = WIDEHISTCOUNTER_GMONTYPE;
+ else
+ gm.histcounter_type = HISTCOUNTER_GMONTYPE;
gm.spare[0] = gm.spare[1] = 0;
/* Write out the gmon header */
@@ -400,6 +410,7 @@ pmcpl_gmon_process(struct pmcstat_proces
struct pmcstat_gmonfile *pgf;
uintfptr_t bucket;
HISTCOUNTER *hc;
+ WIDEHISTCOUNTER *whc;
pmc_id_t pmcid;
(void) nsamples; (void) usermode; (void) cpu;
@@ -437,6 +448,14 @@ pmcpl_gmon_process(struct pmcstat_proces
*/
pgf = pmcstat_image_find_gmonfile(image, pmcid);
if (pgf == NULL) {
+ if (hc_sz == 0) {
+ /* Determine the correct histcounter size. */
+ if (args.pa_flags & FLAG_DO_WIDE_GPROF_HC)
+ hc_sz = sizeof(WIDEHISTCOUNTER);
+ else
+ hc_sz = sizeof(HISTCOUNTER);
+ }
+
if ((pgf = calloc(1, sizeof(*pgf))) == NULL)
err(EX_OSERR, "ERROR:");
@@ -448,7 +467,7 @@ pmcpl_gmon_process(struct pmcstat_proces
pgf->pgf_nbuckets = (image->pi_end - image->pi_start) /
FUNCTION_ALIGNMENT; /* see <machine/profile.h> */
pgf->pgf_ndatabytes = sizeof(struct gmonhdr) +
- pgf->pgf_nbuckets * sizeof(HISTCOUNTER);
+ pgf->pgf_nbuckets * hc_sz;
pgf->pgf_nsamples = 0;
pgf->pgf_file = NULL;
@@ -474,14 +493,25 @@ pmcpl_gmon_process(struct pmcstat_proces
assert(bucket < pgf->pgf_nbuckets);
- hc = (HISTCOUNTER *) ((uintptr_t) pgf->pgf_gmondata +
- sizeof(struct gmonhdr));
-
- /* saturating add */
- if (hc[bucket] < 0xFFFFU) /* XXX tie this to sizeof(HISTCOUNTER) */
- hc[bucket]++;
- else /* mark that an overflow occurred */
- pgf->pgf_overflow = 1;
+ if (args.pa_flags & FLAG_DO_WIDE_GPROF_HC) {
+ whc = (WIDEHISTCOUNTER *) ((uintptr_t) pgf->pgf_gmondata +
+ sizeof(struct gmonhdr));
+
+ /* saturating add */
+ if (whc[bucket] < WIDEHISTCOUNTER_MAX)
+ whc[bucket]++;
+ else /* mark that an overflow occurred */
+ pgf->pgf_overflow = 1;
+ } else {
+ hc = (HISTCOUNTER *) ((uintptr_t) pgf->pgf_gmondata +
+ sizeof(struct gmonhdr));
+
+ /* saturating add */
+ if (hc[bucket] < HISTCOUNTER_MAX)
+ hc[bucket]++;
+ else /* mark that an overflow occurred */
+ pgf->pgf_overflow = 1;
+ }
pgf->pgf_nsamples++;
}
Modified: stable/10/usr.sbin/pmcstat/pmcstat.8
==============================================================================
--- stable/10/usr.sbin/pmcstat/pmcstat.8 Thu Jan 14 21:59:43 2016 (r294045)
+++ stable/10/usr.sbin/pmcstat/pmcstat.8 Thu Jan 14 22:02:21 2016 (r294046)
@@ -25,7 +25,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd May 27, 2015
+.Dd November 18, 2015
.Dt PMCSTAT 8
.Os
.Sh NAME
@@ -49,6 +49,7 @@
.Op Fl a Ar pathname
.Op Fl c Ar cpu-spec
.Op Fl d
+.Op Fl e
.Op Fl f Ar pluginopt
.Op Fl g
.Op Fl k Ar kerneldir
@@ -260,6 +261,12 @@ The default is to measure events for the
.Fl P ,
or
.Fl S ) .
+.It Fl e
+Specify that the gprof profile files will use a wide history counter.
+These files are produced in a format compatible with
+.Xr gprof 1 .
+However, other tools that cannot fully parse a BSD-style
+gmon header might be unable to correctly parse these files.
.It Fl f Ar pluginopt
Pass option string to the active plugin.
.br
Modified: stable/10/usr.sbin/pmcstat/pmcstat.c
==============================================================================
--- stable/10/usr.sbin/pmcstat/pmcstat.c Thu Jan 14 21:59:43 2016 (r294045)
+++ stable/10/usr.sbin/pmcstat/pmcstat.c Thu Jan 14 22:02:21 2016 (r294046)
@@ -506,6 +506,7 @@ pmcstat_show_usage(void)
"\t -a <file>\t print sampled PCs and callgraph to \"file\"\n"
"\t -c cpu-list\t set cpus for subsequent system-wide PMCs\n"
"\t -d\t\t (toggle) track descendants\n"
+ "\t -e\t\t use wide history counter for gprof(1) output\n"
"\t -f spec\t pass \"spec\" to as plugin option\n"
"\t -g\t\t produce gprof(1) compatible profiles\n"
"\t -k dir\t\t set the path to the kernel\n"
@@ -627,7 +628,7 @@ main(int argc, char **argv)
CPU_COPY(&rootmask, &cpumask);
while ((option = getopt(argc, argv,
- "CD:EF:G:M:NO:P:R:S:TWa:c:df:gk:l:m:n:o:p:qr:s:t:vw:z:")) != -1)
+ "CD:EF:G:M:NO:P:R:S:TWa:c:def:gk:l:m:n:o:p:qr:s:t:vw:z:")) != -1)
switch (option) {
case 'a': /* Annotate + callgraph */
args.pa_flags |= FLAG_DO_ANNOTATE;
@@ -668,6 +669,10 @@ main(int argc, char **argv)
args.pa_required |= FLAG_HAS_PROCESS_PMCS;
break;
+ case 'e': /* wide gprof metrics */
+ args.pa_flags |= FLAG_DO_WIDE_GPROF_HC;
+ break;
+
case 'F': /* produce a system-wide calltree */
args.pa_flags |= FLAG_DO_CALLGRAPHS;
args.pa_plugin = PMCSTAT_PL_CALLTREE;
@@ -1022,6 +1027,13 @@ main(int argc, char **argv)
"ERROR: options -g/-G/-m/-T require sampling PMCs or -R to be specified."
);
+ /* check if -e was specified without -g */
+ if ((args.pa_flags & FLAG_DO_WIDE_GPROF_HC) &&
+ !(args.pa_flags & FLAG_DO_GPROF))
+ errx(EX_USAGE,
+"ERROR: option -e requires gprof mode to be specified."
+ );
+
/* check if -O was spuriously specified */
if ((args.pa_flags & FLAG_HAS_OUTPUT_LOGFILE) &&
(args.pa_required & FLAG_HAS_OUTPUT_LOGFILE) == 0)
@@ -1500,14 +1512,24 @@ main(int argc, char **argv)
"ERROR: Cannot retrieve driver statistics");
if (ds_start.pm_intr_bufferfull != ds_end.pm_intr_bufferfull &&
args.pa_verbosity > 0)
- warnx("WARNING: some samples were dropped.\n"
-"Please consider tuning the \"kern.hwpmc.nsamples\" tunable."
+ warnx(
+"WARNING: sampling was paused at least %u time%s.\n"
+"Please consider tuning the \"kern.hwpmc.nsamples\" tunable.",
+ ds_end.pm_intr_bufferfull -
+ ds_start.pm_intr_bufferfull,
+ ((ds_end.pm_intr_bufferfull -
+ ds_start.pm_intr_bufferfull) != 1) ? "s" : ""
);
if (ds_start.pm_buffer_requests_failed !=
ds_end.pm_buffer_requests_failed &&
args.pa_verbosity > 0)
- warnx("WARNING: some events were discarded.\n"
-"Please consider tuning the \"kern.hwpmc.nbuffers\" tunable."
+ warnx(
+"WARNING: at least %u event%s were discarded while running.\n"
+"Please consider tuning the \"kern.hwpmc.nbuffers\" tunable.",
+ ds_end.pm_buffer_requests_failed -
+ ds_start.pm_buffer_requests_failed,
+ ((ds_end.pm_buffer_requests_failed -
+ ds_start.pm_buffer_requests_failed) != 1) ? "s" : ""
);
}
Modified: stable/10/usr.sbin/pmcstat/pmcstat.h
==============================================================================
--- stable/10/usr.sbin/pmcstat/pmcstat.h Thu Jan 14 21:59:43 2016 (r294045)
+++ stable/10/usr.sbin/pmcstat/pmcstat.h Thu Jan 14 22:02:21 2016 (r294046)
@@ -55,6 +55,7 @@
#define FLAG_DO_ANALYSIS 0x00020000 /* -g or -G or -m or -T */
#define FLAGS_HAS_CPUMASK 0x00040000 /* -c */
#define FLAG_HAS_DURATION 0x00080000 /* -l secs */
+#define FLAG_DO_WIDE_GPROF_HC 0x00100000 /* -e */
#define DEFAULT_SAMPLE_COUNT 65536
#define DEFAULT_WAIT_INTERVAL 5.0
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