On 05/29/2010 04:19 PM, Steven Rostedt wrote:
On Sat, 2010-05-29 at 14:50 +0300, Avi Kivity wrote:
On 05/29/2010 12:45 AM, Steven Rostedt wrote:
On Fri, 2010-05-28 at 17:42 +0100, Stefan Hajnoczi wrote:
I get parse errors when using Steven Rostedt's trace-cmd tool, too.
Any ideas what is going on here? I can provide more info (e.g. trace
files) if necessary.
Does trace-cmd fail on the same tracepoints? Have you checkout the
latest code?.
I do know it fails on some of the KVM tracerpoints since the formatting
they use is obnoxious.
Isn't there a binary trace for this?
The pretty printing from the kernel handles this fine. But there's
pressure to pass the format to userspace in binary and have the tool
parse it. Currently it uses the print fmt to figure out how to parse.
Using one of the examples that Stefan showed:
kvmmmu/kvm_mmu_get_page: print fmt: "%s %s", ({ const char *ret =
p->buffer + p->len; static const char *access_str[] = { "---", "--x",
"w--", "w-x", "-u-", "-ux", "wu-", "wux" }; union kvm_mmu_page_role
role; role.word = REC->role; trace_seq_printf(p, "sp gfn %llx %u%s q%u%s
%s%s" " %snxe root %u %s%c", REC->gfn, role.level, role.cr4_pae ? "
pae" : "", role.quadrant, role.direct ? " direct" : "",
access_str[role.access], role.invalid ? " invalid" : "", role.nxe ? "" :
"!", REC->root_count, REC->unsync ? "unsync" : "sync", 0); ret; }),
REC->created ? "new" : "existing"
You need a full C parser/interpreter to understand the above.
Right. The tools can fall back to %x/%s based on the structure
descriptor if they can't parse the format string.
--
error compiling committee.c: too many arguments to function
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