Files
gem5/src/mem/drampower.cc
Nikos Nikoleris e50ab5a2ec mem: Use beats_per_clock as the DDR data rate for DRAMPower
The data rate is used by the drampower lib to estimate the power
consumption of the DRAM Core. Previously, we used the formula:

burst_cycles = divCeil(p->tBURST_MAX, p->tCK);
data_rate = p->burst_length / burst_cycles;

to derive the data_rate. However, under certain configurations this
formula computes the wrong result due to rounding errors. This patch
simplifies the way we derive the data_rate by passing the value of the
DRAM parameter beats_per_clock.

Change-Id: Ic8cd35bb4641d9c0a704675d2672a6fe4f4ec13e
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Wendy Elsasser <wendy.elsasser@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/30056
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
2020-07-20 11:47:01 +00:00

149 lines
5.7 KiB
C++

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#include "mem/drampower.hh"
#include "base/intmath.hh"
#include "sim/core.hh"
DRAMPower::DRAMPower(const DRAMCtrlParams* p, bool include_io) :
powerlib(libDRAMPower(getMemSpec(p), include_io))
{
}
Data::MemArchitectureSpec
DRAMPower::getArchParams(const DRAMCtrlParams* p)
{
Data::MemArchitectureSpec archSpec;
archSpec.burstLength = p->burst_length;
archSpec.nbrOfBanks = p->banks_per_rank;
// One DRAMPower instance per rank, hence set this to 1
archSpec.nbrOfRanks = 1;
archSpec.dataRate = p->beats_per_clock;
// For now we can ignore the number of columns and rows as they
// are not used in the power calculation.
archSpec.nbrOfColumns = 0;
archSpec.nbrOfRows = 0;
archSpec.width = p->device_bus_width;
archSpec.nbrOfBankGroups = p->bank_groups_per_rank;
archSpec.dll = p->dll;
archSpec.twoVoltageDomains = hasTwoVDD(p);
// Keep this disabled for now until the model is firmed up.
archSpec.termination = false;
return archSpec;
}
Data::MemTimingSpec
DRAMPower::getTimingParams(const DRAMCtrlParams* p)
{
// Set the values that are used for power calculations and ignore
// the ones only used by the controller functionality in DRAMPower
// All DRAMPower timings are in clock cycles
Data::MemTimingSpec timingSpec;
timingSpec.RC = divCeil((p->tRAS + p->tRP), p->tCK);
timingSpec.RCD = divCeil(p->tRCD, p->tCK);
timingSpec.RL = divCeil(p->tCL, p->tCK);
timingSpec.RP = divCeil(p->tRP, p->tCK);
timingSpec.RFC = divCeil(p->tRFC, p->tCK);
timingSpec.RAS = divCeil(p->tRAS, p->tCK);
// Write latency is read latency - 1 cycle
// Source: B.Jacob Memory Systems Cache, DRAM, Disk
timingSpec.WL = timingSpec.RL - 1;
timingSpec.DQSCK = 0; // ignore for now
timingSpec.RTP = divCeil(p->tRTP, p->tCK);
timingSpec.WR = divCeil(p->tWR, p->tCK);
timingSpec.XP = divCeil(p->tXP, p->tCK);
timingSpec.XPDLL = divCeil(p->tXPDLL, p->tCK);
timingSpec.XS = divCeil(p->tXS, p->tCK);
timingSpec.XSDLL = divCeil(p->tXSDLL, p->tCK);
// Clock period in ns
timingSpec.clkPeriod = (p->tCK / (double)(SimClock::Int::ns));
assert(timingSpec.clkPeriod != 0);
timingSpec.clkMhz = (1 / timingSpec.clkPeriod) * 1000;
return timingSpec;
}
Data::MemPowerSpec
DRAMPower::getPowerParams(const DRAMCtrlParams* p)
{
// All DRAMPower currents are in mA
Data::MemPowerSpec powerSpec;
powerSpec.idd0 = p->IDD0 * 1000;
powerSpec.idd02 = p->IDD02 * 1000;
powerSpec.idd2p0 = p->IDD2P0 * 1000;
powerSpec.idd2p02 = p->IDD2P02 * 1000;
powerSpec.idd2p1 = p->IDD2P1 * 1000;
powerSpec.idd2p12 = p->IDD2P12 * 1000;
powerSpec.idd2n = p->IDD2N * 1000;
powerSpec.idd2n2 = p->IDD2N2 * 1000;
powerSpec.idd3p0 = p->IDD3P0 * 1000;
powerSpec.idd3p02 = p->IDD3P02 * 1000;
powerSpec.idd3p1 = p->IDD3P1 * 1000;
powerSpec.idd3p12 = p->IDD3P12 * 1000;
powerSpec.idd3n = p->IDD3N * 1000;
powerSpec.idd3n2 = p->IDD3N2 * 1000;
powerSpec.idd4r = p->IDD4R * 1000;
powerSpec.idd4r2 = p->IDD4R2 * 1000;
powerSpec.idd4w = p->IDD4W * 1000;
powerSpec.idd4w2 = p->IDD4W2 * 1000;
powerSpec.idd5 = p->IDD5 * 1000;
powerSpec.idd52 = p->IDD52 * 1000;
powerSpec.idd6 = p->IDD6 * 1000;
powerSpec.idd62 = p->IDD62 * 1000;
powerSpec.vdd = p->VDD;
powerSpec.vdd2 = p->VDD2;
return powerSpec;
}
Data::MemorySpecification
DRAMPower::getMemSpec(const DRAMCtrlParams* p)
{
Data::MemorySpecification memSpec;
memSpec.memArchSpec = getArchParams(p);
memSpec.memTimingSpec = getTimingParams(p);
memSpec.memPowerSpec = getPowerParams(p);
return memSpec;
}
bool
DRAMPower::hasTwoVDD(const DRAMCtrlParams* p)
{
return p->VDD2 == 0 ? false : true;
}