include/perf_timer.h: fix rdtscp register clobber list

jty2 · jty2 · commit edcec8a2933a · 2025-06-10T22:38:09.000-05:00
rdtscp also writes to the ECX register.  Fix clobber list so that
register allocation is done correctly by the compiler.

Change-Id: Ie3c6a5ab8fbeae46605642fc7971b0e1504dd7c2
Signed-off-by: jty2 &lt;46021128+jty2@users.noreply.github.com&gt;
diff --git a/benchmarks/lockhammer/include/perf_timer.h b/benchmarks/lockhammer/include/perf_timer.h
@@ -107,7 +107,7 @@ rdtscp(void)
 
     asm volatile("rdtscp" :
              "=a" (tsc.lo_32),
-             "=d" (tsc.hi_32));
+             "=d" (tsc.hi_32) :: "ecx");
 
     return tsc.tsc_64;
 }

Original file line number	Diff line number	Diff line change
`@@ -107,7 +107,7 @@ rdtscp(void)`
`107`	`107`
`108`	`108`	`asm volatile("rdtscp" :`
`109`	`109`	`"=a" (tsc.lo_32),`
`110`		`- "=d" (tsc.hi_32));`
	`110`	`+ "=d" (tsc.hi_32) :: "ecx");`
`111`	`111`
`112`	`112`	`return tsc.tsc_64;`
`113`	`113`	`}`