Prev: [GIT PULL] hwmon updates for 2.6.33, round 1
Next: Async suspend-resume patch w/ completions (was: Re: Async suspend-resume patch w/ rwsems)
From: Tim Bird on 9 Dec 2009 17:50
Add fdd (Function Duration Dump) program to scripts directory.

The script should be 'chmod a+x'-ed.

Signed-off-by: Tim Bird <tim.bird(a)am.sony.com>
---
scripts/fdd | 766 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 766 insertions(+)

--- /dev/null
+++ b/scripts/fdd
@@ -0,0 +1,766 @@
+#!/usr/bin/env python
+#
+# fdd (function duration dump):
+# Read data from an ftrace duration dump, and format various ways.
+#
+# Based on kd (kft dump).
+#
+# Written by Tim Bird
+#
+# Copyright 2009 Sony Corporation of America
+#
+# GPL 2.0 applies
+#
+# ChangeLog:
+# 0.7.2 - 2009/09/22 - add option to specify interrupt routine (int_func)
+# adjust stack handling for int functions, add support for 'Ms time'
+# 0.7.1 - 2009/09/17 - add --fields option
+# 0.7.0 - 2009/07/28 - handle cpu, add filtering, and commmand line
+# option for dump_list, fix func_stack management
+#
+# ToDo:
+#
+
+MAJOR_VERSION = 0
+MINOR_VERSION = 7
+SUBMINOR_VERSION = 2
+
+# define some constants
+UNKNOWN = "-1"
+PROGNAME_UNKNOWN = "unknown_progname"
+PID_UNKNOWN = "-2"
+TIME_UNKNOWN = "0.000000"
+
+import sys, os
+import time
+import re
+
+debug = 0
+
+class stats_class:
+ def __init__(self):
+ self.missing_callers = 0
+ self.total_functions = 0
+
+def dprint(msg):
+ global debug
+ if debug:
+ print msg
+
+def usage():
+ print """Usage: %s [<options>] <trace-filename>
+This program parses the output from a set of function duration trace lines
+
+Options:
+ -d Show a list of functions, sorted by calltime and filtered
+ an expressions (if any).
+ -n <num> Only show the <num> most time-consuming functions.
+ -t <time> Only show functions with time greater than <time>.
+ -i <int_func> Recognize <int_func> as an interrupt function. This
+ results in special handling of that function.
+ -e <expr> Filter data by given expression. Currently supported
+ expressions are: 'cpu==x' and 'pid==y'
+ -f <format> Show columns indicated by <format> string. Each field is
+ represented by a single character. See '--fields'.
+ The default format string is "fctal", which shows
+ "function, count, time, average, local time" in that order.
+ --fields Show available fields and their format chars.
+ -l Show long listing (format string is "fctalrsmnx").
+ Use a wide terminal window for this, if possible.
+ -s <col-ID> Sort by the column with the specified ID. Can be one
+ of: f,c,t,a,s,l. Default is to sort by total time, 't'.
+ -w Show warnings while reading log data, including warnings
+ about functions dropped due to missing trace information.
+ -z Show some statistics about the data and parse warnings.
+ -h, --help Show this usage help.
+ -V, --version Show version information.
+""" % os.path.basename(sys.argv[0])
+ sys.exit(1)
+
+def show_output_fields():
+ print """Field help for %s:
+Available fields, identified by format character, are:
+ f = Function name
+ c = Count - number of times function was called
+ t = Time - total time spent in this function
+ a = Average - average time per function call
+ l = Local time - time not spent in sub-routines
+ This is the total time of the function, minus the sub-time,
+ and usually gives a good indication of how long a function
+ takes to do its own work. Be careful interpreting this value
+ when using filters, since sub-functions (and their time) may
+ be omitted from the trace.
+ r = Range - minimum and maximum times for a single call
+ s = Sub-time - time spent in sub-routines
+ m = Max sub-routine - name of sub-routine with max time
+ n = Max sub-routine count - # of times max sub-routine was called
+ x = Max sub-routine cost - time spent in calls to max sub-routines
+ u = Sub-routine list - this feature is experimental
+""" % os.path.basename(sys.argv[0])
+ sys.exit(1)
+
+class func_node:
+ sort_order = "t"
+ def __init__(self, name, pid):
+ self.name = name
+ self.callers = []
+ # times are int(nanoseconds)
+ self.total_time = 0
+ self.min = 99999999999
+ self.max = 0
+ self.subs = []
+ self.sub_time = 0
+ self.sub_list = {}
+
+ def get_name(self):
+ return self.name
+
+ def add_call(self, caller, fc):
+ dur = int(fc.duration * 1000000000)
+ dprint("in add_call: func: %s, caller: %s, pid: %s, dur: %s" % \
+ (self.name, caller, fc.pid, dur))
+ self.callers.append((caller, fc.pid, dur))
+ self.total_time += dur
+ dprint("%s total_time=%d" % (self.name, self.time()))
+ if dur < self.min:
+ self.min = dur
+ if dur > self.max:
+ self.max = dur
+ dprint("%s local_time=%d" % (self.name, self.local_time()))
+
+ def add_sub(self, fc):
+ dprint("func: %s, sub: %s, pid: %s, dur: %s" % \
+ (fc.name, self.name, fc.pid, fc.duration))
+ dur = int(fc.duration * 1000000000)
+ self.subs.append((fc.name, fc.pid, dur))
+ self.sub_list[fc.name] = 1
+ self.sub_time += dur
+ dprint("new %s sub_time=%1.3f" % (self.name, self.get_sub_time()))
+ dprint("%s local_time=%d" % (self.name, self.local_time()))
+
+ def time(self):
+ return self.total_time/1000
+
+ def call_count(self):
+ return len(self.callers)
+
+ def avg_time(self):
+ count = len(self.callers)
+ if self.total_time==0:
+ return 0
+ else:
+ return ((self.total_time)/1000)/count
+
+ def time_range(self):
+ count = self.call_count()
+ if count >= 1:
+ return "(%d-%d)" % (self.min/1000, self.max/1000)
+ else:
+ return ""
+
+ def get_sub_time(self):
+ return float(self.sub_time)/1000
+
+ def local_time(self):
+ if self.total_time!=0:
+ return (self.total_time - self.sub_time)/1000
+ else:
+ return 0
+
+ def sub_list(self):
+ return str(self.sub_list.keys())
+
+ def __cmp__(self, other):
+ if self.sort_order == "t":
+ return cmp(self.total_time, other.total_time)
+ if self.sort_order == "f":
+ return cmp(self.name, other.name)
+ if self.sort_order == "c":
+ return cmp(self.call_count(), other.call_count())
+ if self.sort_order == "a":
+ return cmp(self.avg_time(), other.avg_time())
+ if self.sort_order == "s":
+ return cmp(self.sub_time, other.sub_time)
+ if self.sort_order == "l":
+ return cmp(self.local_time(), other.local_time())
+ # huh? no match, sort by total time
+ return cmp(self.total_time, other.total_time)
+
+class func_call:
+ def __init__(self, name, depth, calltime, duration, endtime,
+ cpu, prog_name, pid, line_no):
+ self.name = name
+ self.depth = depth
+ # times are in float(seconds)
+ self.calltime = float(calltime)
+ self.duration = float(duration)/1000000
+ if endtime==TIME_UNKNOWN:
+ self.endtime = self.calltime + self.duration
+ else:
+ self.endtime = float(endtime)
+
+ self.cpu = cpu
+ self.prog_name = prog_name
+ self.pid = pid
+ self.line_no = line_no
+ def __repr__(self):
+ return "func_call: %f:%s" % (self.calltime, self.name)
+
+def cmp_func_calls(a, b):
+ return cmp(a.calltime, b.calltime)
+
+def dump_funcs(funcs):
+ test_keys = ["free_pid", "free_pidmap", "call_rcu", "__call_rcu"]
+ for (key, value) in funcs.items():
+ if key not in test_keys:
+ continue
+ print "func:%s" % key
+ print " time: %s, call_count: %s, avg_time: %s, local_time: %s, sub_time: %s" % (value.time(), value.call_count(), value.avg_time(), value.local_time(), value.sub_time)
+
+
+def get_max_sub(parent_func):
+ global funcs_for_max_sub
+
+ # stupid kludge for passing funcs here through a global
+ funcs = funcs_for_max_sub
+ max_sub = None
+ for (name, pid, duration) in parent_func.subs:
+ if funcs.has_key(name):
+ sub_func = funcs[name]
+ if not max_sub:
+ max_sub = sub_func
+ else:
+ if sub_func.time() > max_sub.time():
+ max_sub = sub_func
+
+ return max_sub
+
+def max_sub_name(parent_func):
+ max_sub = get_max_sub(parent_func)
+ if max_sub:
+ return max_sub.get_name()
+ else:
+ return ""
+
+def max_sub_count(parent_func):
+ global funcs_for_max_sub
+
+ max_sub = get_max_sub(parent_func)
+
+ funcs = funcs_for_max_sub
+ if max_sub:
+ ms_name = max_sub.get_name()
+ ms_count = 0
+ for (name, pid, duration) in parent_func.subs:
+ if funcs.has_key(name):
+ if name == ms_name:
+ ms_count = ms_count + 1
+ return ms_count
+ else:
+ return 0
+
+def max_sub_time(parent_func):
+ max_sub = get_max_sub(parent_func)
+ if max_sub:
+ return max_sub.time()
+ else:
+ return 0
+
+class display_flags:
+ pass
+
+# print errors or warnings for missing fields
+def check_fields(fields):
+ global show_warnings
+
+ if "TASK/PID" not in fields and show_warnings:
+ print "Warning: trace log is missing TASK/PID field"
+ print "Using this field helps with some calculations"
+ print "Try: echo duration-proc >/debug/tracing/trace_options"
+
+# parse lines from ftrace output
+# by default, each line consists of:
+# CPU CALLTIME | DURATION | FUNCTION CALLS
+# the 3rd commented line may be a key to the printed fields
+#
+# Here's a sample line, with default options (cpu, duration):
+# 0) 100.123456789 | 10.167 us | mem_serial_in();
+#
+# here's a sample line with proc turned on:
+# 0) tail-585 | 706.541604750 | 13.834 us | kmem_cache_alloc
+#
+# Here's a sample line, with abstime turned on:
+# note cpu is with calltime!!
+# 582.159156 | 0) 100.123456789 | 576.000 us | }
+#
+# Here's a sample line, with abstime and proc turned on:
+# note cpu is with proc info!!
+# 582.159156 | 0) ash-547 | 9.833 us | fd_install();
+#
+# NOTE: Handling this variable format is a big pain!
+
+def parse_funcduration_lines(lines):
+ global stats
+
+ func_list = {}
+ pids = {}
+
+
+ fields = ["CPU", "CALLTIME", "DURATION", "FUNCTION", "CALLS"]
+
+ non_white_pat = re.compile("[^ ]")
+ progname = PROGNAME_UNKNOWN
+ pid = PID_UNKNOWN
+ abstime = TIME_UNKNOWN
+ cpu = "0"
+
+ # find start line:
+ line_no = 0
+ for line in lines:
+ line_no += 1
+
+ # skip blank lines
+ if not line.strip():
+ continue
+
+ # scan comment lines for the field key
+ if line.startswith("#"):
+ # see if it's the key
+ if line.find("FUNCTION")!=-1:
+ fields = line[1:].split()
+ dprint("fields=%s" % fields)
+ check_fields(fields)
+ continue
+
+ line = line.strip()
+ dprint("%d: line=%s" % (line_no, line))
+
+ # skip comment lines
+ if line.find("/*") != -1:
+ continue
+
+ # possible line formats are:
+ # 1: cpu) calltime | duration units | function
+ # 2: abstime | cpu) calltime | duration units | function
+ # 3: abstime | cpu) task-pid | calltime | duration units | function
+ # 4: calltime | duration units | function
+ # 5: abstime | calltime | duration units | function
+ # 6: task-pid | calltime | duration units | function
+
+ # parse CPU separately, because it doesn't use a
+ # regular delimiter
+
+ if "CPU" in fields:
+ # last item prior to first ')' is cpu number
+ items = line.split(")")
+ front_part = items[0]
+ front_list = front_part.split()
+ cpu = int(front_list[-1])
+ # remake string without cpu
+ del(front_list[-1])
+ front_part = " ".join(front_list)
+ line = front_part+")".join(items[1:])
+
+ parts = line.split("|")
+ if "TIME" in fields:
+ time_part = parts[0]
+ del(parts[0])
+ prev_time = abstime
+ abstime = time_part.strip()
+
+ if "TASK/PID" in fields:
+ proc_part = parts[0]
+ del(parts[0])
+
+ # get progname and pid
+ last_dash = proc_part.rfind("-")
+ progname = proc_part[:last_dash]
+ pid = proc_part[last_dash+1:].strip()
+
+ calltime = parts[0].strip()
+ dur_info = parts[1].split()
+ func_part = parts[2]
+
+ # parse duration information
+ overhead = ""
+ duration = UNKNOWN
+ units = "us"
+ # check for overhead
+ if dur_info[0]=="+" or dur_info[0]=="!":
+ overhead = dur_info[0]
+ dur_info = dur_info[1:]
+ # now get duration
+ duration = dur_info[0]
+ units = dur_info[1]
+
+ # parse function and depth
+ try:
+ m = non_white_pat.search(func_part)
+ func_depth = m.start()/2
+ except:
+ func_depth = 0
+ func_name = func_part.split()[0]
+
+ dprint("task=%s, pid=%s, func_name=%s, func_depth=%s" % \
+ (progname, pid, func_name, func_depth))
+
+ if func_name.startswith("/*"):
+ # skip trace_marker comments
+ continue
+
+ # record function in list
+ fc = func_call(func_name, func_depth, calltime, \
+ duration, abstime, cpu, progname, pid, line_no)
+ if func_list.has_key(cpu):
+ func_list[cpu].append(fc)
+ else:
+ func_list[cpu] = [fc]
+
+ return (func_list)
+
+# func_list is the list of functions, sorted by call entry time
+def generate_stat_info(func_list):
+ funcs = {}
+ root_list = []
+
+ for fl in func_list.values():
+ generate_stat_info_for_cpu(fl, funcs, root_list)
+
+ return(funcs, root_list)
+
+def generate_stat_info_for_cpu(func_list, funcs, root_list):
+ global int_func
+
+ NO_PID = "-1"
+
+ cur_pid = NO_PID
+ # func_stacks[pid] = [list of active funcs]
+ func_stack_for_pid = {}
+ func_stack = []
+
+ for fc in func_list:
+ stats.total_functions += 1
+
+ # determine caller here, using active func_stack
+ caller = UNKNOWN
+
+ # First, detect pid change and change stacks
+ if cur_pid != fc.pid:
+ # save old stack
+ func_stack_for_pid[cur_pid] = func_stack
+ cur_pid = fc.pid
+ # get new stack
+ try:
+ func_stack = func_stack_for_pid[cur_pid]
+ except:
+ func_stack = []
+
+
+ # manage the active function stack
+ # remove expired functions
+ # function is expired if it's depth is greater than current
+ # function depth
+ # function is expired if it's endtime is less than current
+ # function calltime
+ while func_stack and func_stack[-1].depth > fc.depth:
+ dprint("expiring %s from func_stack due to depth" % func_stack[-1])
+ func_stack.pop()
+ while func_stack and func_stack[-1].endtime < fc.calltime:
+ dprint("expiring %s from func_stack due to endtime" % func_stack[-1])
+ func_stack.pop()
+
+ if fc.depth==1 or fc.name==int_func:
+ root_list.append(fc)
+ else:
+ # find caller in active func stack
+ # cc = caller_candidate
+ if func_stack:
+ cc = func_stack[-1]
+ if cc.calltime < fc.calltime and \
+ cc.endtime >= cc.endtime and \
+ cc.depth == fc.depth-1:
+ caller = cc.name
+ dprint("found caller=%s" % caller)
+ else:
+ print "Warning: %s (line %d) is not caller of %s (at line %d)" % \
+ (cc.name, cc.line_no, fc.name, fc.line_no)
+ else:
+ if show_warnings:
+ print "Warning: empty func_stack for func %s at depth %d" % (fc, fc.depth)
+
+ # FIXTHIS - track stats by CPU?
+ if not funcs.has_key(fc.name):
+ funcs[fc.name] = func_node(fc.name, fc.pid)
+
+ funcs[fc.name].add_call(caller, fc)
+
+ if caller != UNKNOWN:
+ if not funcs.has_key(caller):
+ funcs[caller] = func_node(caller, fd.pid)
+ funcs[caller].add_sub(fc)
+ else:
+ if fc.depth != 1:
+ stats.missing_callers += 1
+ if show_warnings:
+ print "Warning: Could not find caller for %s at depth %d" % (fc, fc.depth)
+
+ # add this function to bottom of stack
+ func_stack.append(fc)
+ dprint("cur_pid=%s, func_stack = %s" % (cur_pid, func_stack))
+
+ if (debug):
+ dump_funcs(funcs)
+
+ return(funcs, root_list)
+
+class column:
+ def __init__(self, id, name, len, format, data_func):
+ self.id = id
+ self.name = name
+ self.format = format
+ self.tlen = len
+ self.data_func = data_func
+ def show_title(self):
+ format = "%-"+"%ss" % self.tlen
+ print format % self.name,
+ def show_bar(self):
+ print "-"*self.tlen,
+ def show_data(self, arg):
+ print self.format % self.data_func(arg),
+
+def init_columns():
+ global columns
+
+ columns = {}
+ columns['f'] = column('f', "Function", 30, "%-30s", func_node.get_name)
+ columns['c'] = column('c', "Count", 5, "%5d", func_node.call_count)
+ columns['t'] = column('t', "Time", 8, "%8d", func_node.time)
+ columns['a'] = column('a', "Average", 8, "%8d", func_node.avg_time)
+ columns['r'] = column('r', "Range", 18, "%18s", func_node.time_range)
+ columns['s'] = column('s', "Sub-time", 8, "%8d", func_node.get_sub_time)
+ columns['l'] = column('l', "Local", 8, "%8d", func_node.local_time)
+ columns['m'] = column('m', "Max-sub", 30, "%30s", max_sub_name)
+ columns['n'] = column('n', "Ms cnt", 6, "%6d", max_sub_count)
+ columns['u'] = column('u', "Sub list", 20, "%s", func_node.sub_list)
+ columns['x'] = column('x', "Ms time", 8, "%8d", max_sub_time)
+
+
+def show_func_stats(funcs, show_count, show_time, col_list):
+ global columns, funcs_for_max_sub
+
+ funcs_for_max_sub = funcs
+ funclist = funcs.values()
+ funclist.sort()
+ funclist.reverse()
+
+ if not col_list:
+ col_list = "fctal"
+
+ # filter the col_list to only valid columns
+ col_list_old = col_list
+ col_list = ""
+ for col_id in col_list_old:
+ if not columns.has_key(col_id):
+ print "Invalid column id: %s" % col_id
+ else:
+ col_list = col_list + col_id
+
+ # show titles
+ for col_id in col_list:
+ col = columns[col_id]
+ col.show_title()
+ print
+
+ # show bar underneath title
+ for col_id in col_list:
+ col = columns[col_id]
+ col.show_bar()
+ print
+
+ # show data
+ i = 0
+ for func in funclist:
+ if show_time and func.total_time < show_time:
+ continue
+ if show_count:
+ i = i+1
+ if i>show_count:
+ continue
+ for col_id in col_list:
+ col = columns[col_id]
+ col.show_data(func)
+ print
+
+def dump_list(func_list):
+ print "# CALLTIME DURATION FUNCTION CALLS"
+ print "# | | | | | | |"
+
+ cpu_list = func_list.keys()
+ cpu_list.sort()
+
+ for cpu in cpu_list:
+ for fc in func_list[cpu]:
+ print "%d) %15.9f | %9.3f |%s%s" % (fc.cpu, fc.calltime, \
+ fc.duration*1000000, " "*fc.depth, fc.name)
+
+filter_warning_emitted = 0
+
+def filter_match(filter_expr, fc):
+ global filter_warning_emitted
+
+ if filter_expr.startswith("cpu=="):
+ match_cpu = int(filter_expr[5:])
+ if fc.cpu == match_cpu:
+ return 1
+ else:
+ return 0
+
+ if filter_expr.startswith("pid=="):
+ match_pid = filter_expr[5:]
+ if fc.pid == match_pid:
+ return 1
+ else:
+ return 0
+
+ if not filter_warning_emitted:
+ filter_warning_emitted = 1
+ print "Warning: unknown filter: '%s' - unable to process" % filter_expr
+ # raise an error here?
+ return 1
+
+
+def filter_list(func_list, filter_expr):
+ for cpu in func_list.keys():
+ fl = func_list[cpu]
+ new_fl = []
+ for fc in func_list[cpu]:
+ if filter_match(filter_expr, fc):
+ new_fl.append(fc)
+ func_list[cpu] = new_fl
+
+def main():
+ global debug, show_warnings
+ global show_fdd_stats, stats
+ global int_func
+
+ filein = ""
+ show_count = 0
+ show_time = 0
+ debug = 0
+ col_list = ""
+ sort_order = "t"
+ show_warnings = 0
+ filter_expr = ""
+ show_stats = 1
+ show_dump_list = 0
+ int_func = ""
+
+ stats = stats_class()
+ show_fdd_stats = 0
+
+ args = sys.argv[1:]
+ if "-h" in args or "--help" in args:
+ usage()
+ if "--fields" in args:
+ show_output_fields()
+ if "-V" in args or "--version" in args:
+ print "Function Duration Dump - version %s.%s.%s" % \
+ (MAJOR_VERSION, MINOR_VERSION, SUBMINOR_VERSION)
+ sys.exit(0)
+ if "-l" in args:
+ col_list = "fctalrsmnx"
+ args.remove("-l")
+ if "-d" in args:
+ show_stats = 0
+ show_dump_list = 1
+ args.remove("-d")
+ if "-n" in args:
+ i = args.index("-n")
+ show_count = int(args[i+1])
+ del(args[i+1])
+ del(args[i])
+ if "-i" in args:
+ i = args.index("-i")
+ int_func = args[i+1]
+ del(args[i+1])
+ del(args[i])
+ if "-t" in args:
+ i = args.index("-t")
+ show_time = int(args[i+1])
+ del(args[i+1])
+ del(args[i])
+ if "-f" in args:
+ i = args.index("-f")
+ col_list = args[i+1]
+ del(args[i+1])
+ del(args[i])
+ if "-e" in args:
+ i = args.index("-e")
+ filter_expr = args[i+1]
+ del(args[i+1])
+ del(args[i])
+ if "-s" in args:
+ i = args.index("-s")
+ sort_order = args[i+1]
+ del(args[i+1])
+ del(args[i])
+ if sort_order not in ["f", "c", "t", "a", "s", "l"]:
+ print "Invalid sort order. Use '-h' for help."
+ sys.exit(1)
+ if "-w" in args:
+ show_warnings = 1
+ args.remove("-w")
+ if "-z" in args:
+ show_fdd_stats = 1
+ args.remove("-z")
+ if "--debug" in args:
+ debug = 1
+ args.remove("--debug")
+
+ if len(args)==1:
+ filein = args[0]
+
+ if not filein:
+ print "No filename specified. See usage for help. (Use -h)"
+ sys.exit(1)
+
+ try:
+ lines = open(filein,"r").readlines()
+ except:
+ print "Problem opening file: %s" % filein
+ sys.exit(1)
+
+ func_list = parse_funcduration_lines(lines)
+
+ if filter_expr:
+ filter_list(func_list, filter_expr)
+
+ # sort call list by start time
+ for cpu in func_list.keys():
+ func_list[cpu].sort(cmp_func_calls)
+
+ # show functions sorted by call-time
+ # this can be used in place of cat <file> | sort -k2
+ if show_dump_list:
+ dump_list(func_list)
+
+ if show_stats:
+ (funcs, root_list) = generate_stat_info(func_list)
+
+ init_columns()
+ func_node.sort_order = sort_order
+ show_func_stats(funcs, show_count, show_time, col_list)
+
+ if show_fdd_stats:
+ print "Trace stats:"
+ print " %d total functions" % stats.total_functions
+ print " missing callers: %d" % stats.missing_callers
+
+if __name__ == "__main__":
+ try:
+ main()
+ except IOError:
+ # skip broken pipe errors (from e.g. "kd foo | head")
+ (exc_type, exc_value, exc_trace) = sys.exc_info()
+ if str(exc_value)!="[Errno 32] Broken pipe":
+ raise


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
 | 
Pages: 1
Prev: [GIT PULL] hwmon updates for 2.6.33, round 1
Next: Async suspend-resume patch w/ completions (was: Re: Async suspend-resume patch w/ rwsems)