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authorMauro Carvalho Chehab <mchehab@kernel.org>2023-02-08 15:18:54 +0100
committerMauro Carvalho Chehab <mchehab@kernel.org>2023-02-08 15:18:54 +0100
commit94817983fb2ccd1869ed0c5a763317a45283a272 (patch)
tree5517dcf434a416074756acd9f482b0e7bbf01baf /scripts/tracing/ftrace-bisect.sh
parent7120d6bfd6d0b26b49958f429701996f2d3e2c2a (diff)
parent4ec5183ec48656cec489c49f989c508b68b518e3 (diff)
Merge tag 'v6.2-rc7' into media_tree
Linux 6.2-rc7 * tag 'v6.2-rc7': (1549 commits) Linux 6.2-rc7 fbcon: Check font dimension limits efi: fix potential NULL deref in efi_mem_reserve_persistent kernel/irq/irqdomain.c: fix memory leak with using debugfs_lookup() HV: hv_balloon: fix memory leak with using debugfs_lookup() mtk_sgmii: enable PCS polling to allow SFP work net: mediatek: sgmii: fix duplex configuration net: mediatek: sgmii: ensure the SGMII PHY is powered down on configuration MAINTAINERS: update SCTP maintainers MAINTAINERS: ipv6: retire Hideaki Yoshifuji mailmap: add John Crispin's entry MAINTAINERS: bonding: move Veaceslav Falico to CREDITS net: openvswitch: fix flow memory leak in ovs_flow_cmd_new net: ethernet: mtk_eth_soc: disable hardware DSA untagging for second MAC virtio-net: Keep stop() to follow mirror sequence of open() efi: Accept version 2 of memory attributes table ceph: blocklist the kclient when receiving corrupted snap trace ceph: move mount state enum to super.h selftests: net: udpgso_bench_tx: Cater for pending datagrams zerocopy benchmarking selftests: net: udpgso_bench: Fix racing bug between the rx/tx programs ...
Diffstat (limited to 'scripts/tracing/ftrace-bisect.sh')
-rwxr-xr-xscripts/tracing/ftrace-bisect.sh34
1 files changed, 26 insertions, 8 deletions
diff --git a/scripts/tracing/ftrace-bisect.sh b/scripts/tracing/ftrace-bisect.sh
index 926701162bc8..bb4f59262bbe 100755
--- a/scripts/tracing/ftrace-bisect.sh
+++ b/scripts/tracing/ftrace-bisect.sh
@@ -12,7 +12,7 @@
# (note, if this is a problem with function_graph tracing, then simply
# replace "function" with "function_graph" in the following steps).
#
-# # cd /sys/kernel/debug/tracing
+# # cd /sys/kernel/tracing
# # echo schedule > set_ftrace_filter
# # echo function > current_tracer
#
@@ -20,22 +20,40 @@
#
# # echo nop > current_tracer
#
-# # cat available_filter_functions > ~/full-file
+# Starting with v5.1 this can be done with numbers, making it much faster:
+#
+# The old (slow) way, for kernels before v5.1.
+#
+# [old-way] # cat available_filter_functions > ~/full-file
+#
+# [old-way] *** Note *** this process will take several minutes to update the
+# [old-way] filters. Setting multiple functions is an O(n^2) operation, and we
+# [old-way] are dealing with thousands of functions. So go have coffee, talk
+# [old-way] with your coworkers, read facebook. And eventually, this operation
+# [old-way] will end.
+#
+# The new way (using numbers) is an O(n) operation, and usually takes less than a second.
+#
+# seq `wc -l available_filter_functions | cut -d' ' -f1` > ~/full-file
+#
+# This will create a sequence of numbers that match the functions in
+# available_filter_functions, and when echoing in a number into the
+# set_ftrace_filter file, it will enable the corresponding function in
+# O(1) time. Making enabling all functions O(n) where n is the number of
+# functions to enable.
+#
+# For either the new or old way, the rest of the operations remain the same.
+#
# # ftrace-bisect ~/full-file ~/test-file ~/non-test-file
# # cat ~/test-file > set_ftrace_filter
#
-# *** Note *** this will take several minutes. Setting multiple functions is
-# an O(n^2) operation, and we are dealing with thousands of functions. So go
-# have coffee, talk with your coworkers, read facebook. And eventually, this
-# operation will end.
-#
# # echo function > current_tracer
#
# If it crashes, we know that ~/test-file has a bad function.
#
# Reboot back to test kernel.
#
-# # cd /sys/kernel/debug/tracing
+# # cd /sys/kernel/tracing
# # mv ~/test-file ~/full-file
#
# If it didn't crash.