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# Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# * Neither the name of NVIDIA CORPORATION nor the names of its
# contributors may be used to endorse or promote products derived
# from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
# OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
import NvRules
def get_identifier():
return "MemoryApertureUsage"
def get_name():
return "Memory Aperture Usage"
def get_description():
return "Detection of frequent memory accesses backed by apertures with slower memory bandwidth and higher latency."
def get_section_identifier():
return "MemoryWorkloadAnalysis_Chart"
def apply(handle):
ctx = NvRules.get_context(handle)
action = ctx.range_by_idx(0).action_by_idx(0)
fe = ctx.frontend()
# Metrics ==========================================================================================================
lts__t_sectors_srcunit_tex_peak_pct = action.metric_by_name("lts__t_sectors_srcunit_tex.avg.pct_of_peak_sustained_elapsed").as_double()
lts__t_sectors_srcunit_tex_lookup_miss = action.metric_by_name("lts__t_sectors_srcunit_tex_lookup_miss.sum").as_double()
cc_major = action.metric_by_name("device__attribute_compute_capability_major").as_uint64()
cc_minor = action.metric_by_name("device__attribute_compute_capability_minor").as_uint64()
cc = cc_major * 10 + cc_minor
if (False
or cc == 72
or cc == 87
):
return
# Apertures ========================================================================================================
apertures = {
"peer" : (
"Peer"
),
"sysmem" : (
"System"
)
}
lts__high_utilization_threshold = 50
lts__high_aperture_utilization_threshold = 40
for aperture in apertures:
aperture_info = apertures[aperture]
lts__t_sectors_srcunit_tex_aperture_lookup_miss = action.metric_by_name("lts__t_sectors_srcunit_tex_aperture_{}_lookup_miss.sum".format(aperture)).as_double()
lts__t_sectors_srcunit_tex_aperture_lookup_miss_ratio = 100. * lts__t_sectors_srcunit_tex_aperture_lookup_miss / lts__t_sectors_srcunit_tex_lookup_miss if lts__t_sectors_srcunit_tex_lookup_miss else 0.
if lts__t_sectors_srcunit_tex_peak_pct > lts__high_utilization_threshold and lts__t_sectors_srcunit_tex_aperture_lookup_miss_ratio > lts__high_aperture_utilization_threshold:
message = "{} memory backs {:.1f}% of the data in the L2 cache that was requested by L1TEX and had cache misses in L2. ".format(aperture_info, lts__t_sectors_srcunit_tex_aperture_lookup_miss_ratio)
message += "Fetching data from {} memory is considerably slower than accessing the device's dedicated DRAM, as the data needs to be communicated over PCIE or NVLINK. ".format(aperture_info.lower())
message += "Consider moving frequently accessed data to DRAM before launching this kernel."
if 80 <= cc:
message += " Tweaking the L2 cache policies can help optimizing the cache hit rates for accesses to slower {} memory. ".format(aperture_info.lower())
message += "Lookup CUaccessProperty and policy CU_ACCESS_PROPERTY_PERSISTING for more details."
msg_id = fe.message(NvRules.IFrontend.MsgType_MSG_WARNING, message, "{} Memory Usage".format(aperture_info))
fe.focus_metric(msg_id, "Peak % of L2 Sector Requests from L1TEX", lts__t_sectors_srcunit_tex_peak_pct, NvRules.IFrontend.Severity_SEVERITY_HIGH if lts__t_sectors_srcunit_tex_peak_pct > 75 else NvRules.IFrontend.Severity_SEVERITY_LOW, "{:.2f} < {:.2f}".format(lts__high_utilization_threshold, lts__t_sectors_srcunit_tex_peak_pct))
fe.focus_metric(msg_id, "% of L2 Misses to {} Memory".format(aperture_info), lts__t_sectors_srcunit_tex_aperture_lookup_miss_ratio, NvRules.IFrontend.Severity_SEVERITY_HIGH if lts__t_sectors_srcunit_tex_aperture_lookup_miss_ratio > 75 else NvRules.IFrontend.Severity_SEVERITY_LOW, "{:.2f} < {:.2f}".format(lts__high_aperture_utilization_threshold, lts__t_sectors_srcunit_tex_aperture_lookup_miss_ratio))
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