Hi All,
For a 2 level cache hierarchy with DDR3 (11-11-11) as the DRAM
specs, the number of prefetch requests issued by the L2 prefetcher is high
(very high in some cases) as compared to the number of prefetch requests
responded by the DRAM controller. Any thoughts on it.
The difference becomes almost negligible, when I use an L3 cache and turn
on the prefetchers at the L2. In case of 3 level cache hierarchy, this
equation holds true:
pf_issued at the L2s = Pf hits at the L3 + Pf requests
responded by the DRAM
Here are the actual numbers for a 4 core setup with PARSEC benchmarks:
blackscholes_4c_simlarge_ckpts.rcS.txt:system.mem_ctrls.num_reads::l2.prefetcher
130935 # Number of read requests responded to by this
memory
blackscholes_4c_simlarge_ckpts.rcS.txt:system.l2.prefetcher.prefetcher.num_hwpf_issued
148226 # number of hwpf issued
canneal_4c_simlarge_ckpts.rcS.txt:system.mem_ctrls.num_reads::l2.prefetcher
346384 # Number of read requests responded to by this
memory
canneal_4c_simlarge_ckpts.rcS.txt:system.l2.prefetcher.prefetcher.num_hwpf_issued
354459 # number of hwpf issued
dedup_4c_simlarge_ckpts.rcS.txt:system.mem_ctrls.num_reads::l2.prefetcher
2937725 # Number of read requests responded to by
this memory
dedup_4c_simlarge_ckpts.rcS.txt:system.l2.prefetcher.prefetcher.num_hwpf_issued
3251216 # number of hwpf issued
facesim_4c_simlarge_ckpts.rcS.txt:system.mem_ctrls.num_reads::l2.prefetcher
3443990 # Number of read requests responded to by
this memory
facesim_4c_simlarge_ckpts.rcS.txt:system.l2.prefetcher.prefetcher.num_hwpf_issued
3639481 # number of hwpf issued
ferret_4c_simlarge_ckpts.rcS.txt:system.mem_ctrls.num_reads::l2.prefetcher
2141141 # Number of read requests responded to by
this memory
ferret_4c_simlarge_ckpts.rcS.txt:system.l2.prefetcher.prefetcher.num_hwpf_issued
12161061 # number of hwpf issued
freqmine_4c_simlarge_ckpts.rcS.txt:system.mem_ctrls.num_reads::l2.prefetcher
115625 # Number of read requests responded to by this
memory
freqmine_4c_simlarge_ckpts.rcS.txt:system.l2.prefetcher.prefetcher.num_hwpf_issued
168290 # number of hwpf issued
rtview_4c_simlarge_ckpts.rcS.txt:system.mem_ctrls.num_reads::l2.prefetcher
590098 # Number of read requests responded to by this
memory
rtview_4c_simlarge_ckpts.rcS.txt:system.l2.prefetcher.prefetcher.num_hwpf_issued
863745 # number of hwpf issued
swaptions_4c_simlarge_ckpts.rcS.txt:system.mem_ctrls.num_reads::l2.prefetcher
20308 # Number of read requests responded to by this
memory
swaptions_4c_simlarge_ckpts.rcS.txt:system.l2.prefetcher.prefetcher.num_hwpf_issued
16689699 # number of hwpf issued
vips_4c_simlarge_ckpts.rcS.txt:system.mem_ctrls.num_reads::l2.prefetcher
3361213 # Number of read requests responded to by
this memory
vips_4c_simlarge_ckpts.rcS.txt:system.l2.prefetcher.prefetcher.num_hwpf_issued
3542000 # number of hwpf issued
x264_4c_simlarge_ckpts.rcS.txt:system.mem_ctrls.num_reads::l2.prefetcher
1060135 # Number of read requests responded to by
this memory
x264_4c_simlarge_ckpts.rcS.txt:system.l2.prefetcher.prefetcher.num_hwpf_issued
1805457 # number of hwpf issued
--
*thanks®ards*
*BISWABANDAN*
http://www.cse.iitm.ac.in/~biswa/
“We might fall down, but we will never lay down. We might not be the best,
but we will beat the best! We might not be at the top, but we will rise.”
_______________________________________________
gem5-users mailing list
[email protected]
http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
