freebsd-nq/lib/libpmc/pmc.xscale.3

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.\" $FreeBSD$
.\"
.Dd December 23, 2009
.Dt PMC.XSCALE 3
.Os
.Sh NAME
.Nm pmc.xscale
.Nd measurement events for
.Tn Intel
.Tn XScale
family CPUs
.Sh LIBRARY
.Lb libpmc
.Sh SYNOPSIS
.In pmc.h
.Sh DESCRIPTION
.Tn Intel XScale
CPUs are ARM CPUs based on the ARMv5e core.
.Pp
Second generation cores have 2 counters, while third generation cores
have 4 counters.
Third generation cores also have an increased number of PMC events.
.Pp
.Tn Intel XScale
PMCs are documented in 
.Rs
.%B "3rd Generation Intel XScale Microarchitecture Developer's Manual"
.%D May 2007
.Re
.Ss Event Specifiers (Programmable PMCs)
.Tn Intel XScale
programmable PMCs support the following events:
.Bl -tag -width indent
.It Li IC_FETCH
External memory fetch due to L1 instruction cache miss.
.It Li IC_MISS
Instruction cache or TLB miss.
.It Li DATA_DEPENDENCY_STALLED
A data dependency stalled
.It Li ITLB_MISS
Instruction TLB miss.
.It Li DTLB_MISS
Data TLB miss.
.It Li BRANCH_RETIRED
Branch instruction retired (executed).
.It Li BRANCH_MISPRED
Branch mispredicted.
.It Li INSTR_RETIRED
Instructions retired (executed).
.It Li DC_FULL_CYCLE
L1 data cache buffer full stall.
Event occurs on every cycle the
condition is present.
.It Li DC_FULL_CONTIG
L1 data cache buffer full stall.
Event occurs once for each contiguous sequence of this type of stall.
.It Li DC_ACCESS
L1 data cache access, not including cache operations.
.It Li DC_MISS
L1 data cache miss, not including cache operations.
.It Li DC_WRITEBACK
L1 data cache write-back.
Occurs for each cache line that's written back from the cache.
.It Li PC_CHANGE
Software changed the program counter.
.It Li BRANCH_RETIRED_ALL
Branch instruction retired (executed).
This event counts all branch instructions, indirect or direct.
.It Li INSTR_CYCLE
Count the number of microarchitecture cycles each instruction requires
to issue.
.It Li CP_STALL
Coprocessor stalled the instruction pipeline.
.It Li PC_CHANGE_ALL
Software changed the program counter (includes exceptions).
.It Li PIPELINE_FLUSH
Pipeline flushes due to mispredictions or exceptions.
.It Li BACKEND_STALL
Backend stalled the instruction pipeline.
.It Li MULTIPLIER_USE
Multiplier used.
.It Li MULTIPLIER_STALLED
Multiplier stalled the instruction pipeline.
.It Li DATA_CACHE_STALLED
Data cache stalled the instruction pipeline.
.It Li L2_CACHE_REQ
L2 cache request, not including cache operations.
.It Li L2_CACHE_MISS
L2 cache miss, not including cache operations.
.It Li ADDRESS_BUS_TRANS
Address bus transaction.
.It Li SELF_ADDRESS_BUS_TRANS
Self initiated address bus transaction.
.It Li DATA_BUS_TRANS
Data bus transaction.
.El
.Ss Event Name Aliases  
The following table shows the mapping between the PMC-independent
aliases supported by
.Lb libpmc
and the underlying hardware events used.
.Bl -column "branch-mispredicts" "BRANCH_MISPRED"
.It Em Alias Ta Em Event Ta
.It Li branches Ta Li BRANCH_RETIRED Ta
.It Li branch-mispredicts Ta Li BRANCH_MISPRED Ta
.It Li dc-misses Ta Li DC_MISS Ta
.It Li ic-misses Ta Li IC_MISS Ta
.It Li instructions Ta Li INSTR_RETIRED Ta
.El
.Sh SEE ALSO
.Xr pmc 3 ,
.Xr pmc_cpuinfo 3 ,
.Xr pmclog 3 ,
.Xr hwpmc 4
.Sh HISTORY
The
.Nm pmc
library first appeared in
.Fx 6.0 .
Intel XScale support first appeared in
.Fx 9.0 .
.Sh AUTHORS
The
.Lb libpmc
library was written by
.An "Joseph Koshy"
.Aq jkoshy@FreeBSD.org .
.Pp
Intel XScale support was added by
.An "Rui Paulo"
.Aq rpaulo@FreeBSD.org .
.Sh CAVEATS
The Intel XScale code does not yet support sampling.