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Revision 59a32e2ce5eb809967cac4e718bc527beca83c59 authored by Eric Dumazet on 23 March 2012, 22:02:53 UTC, committed by Linus Torvalds on 23 March 2012, 23:58:42 UTC 
proc: speed up /proc/stat handling
 
On a typical 16 cpus machine, "cat /proc/stat" gives more than 4096 bytes,
and is slow :

  # strace -T -o /tmp/STRACE cat /proc/stat | wc -c
  5826
  # grep "cpu " /tmp/STRACE
  read(0, "cpu  1949310 19 2144714 12117253"..., 32768) = 5826 <0.001504>

Thats partly because show_stat() must be called twice since initial
buffer size is too small (4096 bytes for less than 32 possible cpus)

Fix this by :

 1) Taking into account nr_irqs in the initial buffer sizing.

 2) Using ksize() to allow better filling of initial buffer.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent b908243
Raw File
Makefile.fwinst 
# ==========================================================================
# Installing firmware
#
# We don't include the .config, so all firmware files are in $(fw-shipped-)
# rather than in $(fw-shipped-y) or $(fw-shipped-n).
# ==========================================================================

INSTALL := install
src := $(obj)

# For modules_install installing firmware, we want to see .config
# But for firmware_install, we don't care, but don't want to require it.
-include $(objtree)/.config

include scripts/Kbuild.include
include $(srctree)/$(obj)/Makefile

include scripts/Makefile.host

mod-fw := $(fw-shipped-m)
# If CONFIG_FIRMWARE_IN_KERNEL isn't set, then install the 
# firmware for in-kernel drivers too.
ifndef CONFIG_FIRMWARE_IN_KERNEL
mod-fw += $(fw-shipped-y)
endif

installed-mod-fw := $(addprefix $(INSTALL_FW_PATH)/,$(mod-fw))

installed-fw := $(addprefix $(INSTALL_FW_PATH)/,$(fw-shipped-all))
installed-fw-dirs := $(sort $(dir $(installed-fw))) $(INSTALL_FW_PATH)/.

# Workaround for make < 3.81, where .SECONDEXPANSION doesn't work.
PHONY += $(INSTALL_FW_PATH)/$$(%) install-all-dirs
$(INSTALL_FW_PATH)/$$(%): install-all-dirs
	@true
install-all-dirs: $(installed-fw-dirs)
	@true

quiet_cmd_install = INSTALL $(subst $(srctree)/,,$@)
      cmd_install = $(INSTALL) -m0644 $< $@

$(installed-fw-dirs):
	$(call cmd,mkdir)

$(installed-fw): $(INSTALL_FW_PATH)/%: $(obj)/% | $(INSTALL_FW_PATH)/$$(dir %)
	$(call cmd,install)

PHONY +=  __fw_install __fw_modinst FORCE

.PHONY: $(PHONY)

__fw_install: $(installed-fw)

__fw_modinst: $(installed-mod-fw)
	@:

__fw_modbuild: $(addprefix $(obj)/,$(mod-fw))
	@:

FORCE:

# Read all saved command lines and dependencies for the $(targets) we
# may be building using $(if_changed{,_dep}). As an optimization, we
# don't need to read them if the target does not exist; we will rebuild
# anyway in that case.

targets := $(wildcard $(sort $(targets)))
cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))

ifneq ($(cmd_files),)
  include $(cmd_files)
endif
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