tools/power turbostat: Cache graphics sysfs file descriptors during probe

Snapshots of the graphics sysfs knobs are taken based on file
descriptors. To optimize this process, open the files and cache the file
descriptors during the graphics probe phase. As a result, the previously
cached pathnames become redundant and are removed.

This change aims to streamline the code without altering its functionality.

No functional change intended.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 32 insertions, 50 deletions

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index e5b100b8db24..28513172ffce 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -376,7 +376,6 @@ enum gfx_sysfs_idx {
 };
 
 struct gfx_sysfs_info {
-	const char *path;
 	FILE *fp;
 	unsigned int val;
 	unsigned long long val_ull;
@@ -5766,10 +5765,7 @@ int snapshot_graphics(int idx)
 {
 	int retval;
 
-	if (gfx_info[idx].fp == NULL)
-		gfx_info[idx].fp = fopen_or_die(gfx_info[idx].path, "r");
-	else
-		rewind(gfx_info[idx].fp);
+	rewind(gfx_info[idx].fp);
 
 	switch (idx) {
 	case GFX_rc6:
@@ -6474,6 +6470,12 @@ static void probe_intel_uncore_frequency(void)
 		probe_intel_uncore_frequency_legacy();
 }
 
+static void set_graphics_fp(char *path, int idx)
+{
+	if (!access(path, R_OK))
+		gfx_info[idx].fp = fopen_or_die(path, "r");
+}
+
 static void probe_graphics(void)
 {
 	/* Xe graphics sysfs knobs */
@@ -6481,7 +6483,6 @@ static void probe_graphics(void)
 		FILE *fp;
 		char buf[8];
 		bool gt0_is_gt;
-		int idx;
 
 		fp = fopen("/sys/class/drm/card0/device/tile0/gt0/gtidle/name", "r");
 		if (!fp)
@@ -6500,28 +6501,17 @@ static void probe_graphics(void)
 		else
 			goto next;
 
-		idx = gt0_is_gt ? GFX_rc6 : SAM_mc6;
-		gfx_info[idx].path = "/sys/class/drm/card0/device/tile0/gt0/gtidle/idle_residency_ms";
+		set_graphics_fp("/sys/class/drm/card0/device/tile0/gt0/gtidle/idle_residency_ms", gt0_is_gt ? GFX_rc6 : SAM_mc6);
 
-		idx = gt0_is_gt ? GFX_MHz : SAM_MHz;
-		if (!access("/sys/class/drm/card0/device/tile0/gt0/freq0/cur_freq", R_OK))
-			gfx_info[idx].path = "/sys/class/drm/card0/device/tile0/gt0/freq0/cur_freq";
+		set_graphics_fp("/sys/class/drm/card0/device/tile0/gt0/freq0/cur_freq", gt0_is_gt ? GFX_MHz : SAM_MHz);
 
-		idx = gt0_is_gt ? GFX_ACTMHz : SAM_ACTMHz;
-		if (!access("/sys/class/drm/card0/device/tile0/gt0/freq0/act_freq", R_OK))
-			gfx_info[idx].path = "/sys/class/drm/card0/device/tile0/gt0/freq0/act_freq";
+		set_graphics_fp("/sys/class/drm/card0/device/tile0/gt0/freq0/act_freq", gt0_is_gt ? GFX_ACTMHz : SAM_ACTMHz);
 
-		idx = gt0_is_gt ? SAM_mc6 : GFX_rc6;
-		if (!access("/sys/class/drm/card0/device/tile0/gt1/gtidle/idle_residency_ms", R_OK))
-			gfx_info[idx].path = "/sys/class/drm/card0/device/tile0/gt1/gtidle/idle_residency_ms";
+		set_graphics_fp("/sys/class/drm/card0/device/tile0/gt1/gtidle/idle_residency_ms", gt0_is_gt ? SAM_mc6 : GFX_rc6);
 
-		idx = gt0_is_gt ? SAM_MHz : GFX_MHz;
-		if (!access("/sys/class/drm/card0/device/tile0/gt1/freq0/cur_freq", R_OK))
-			gfx_info[idx].path = "/sys/class/drm/card0/device/tile0/gt1/freq0/cur_freq";
+		set_graphics_fp("/sys/class/drm/card0/device/tile0/gt1/freq0/cur_freq", gt0_is_gt ? SAM_MHz : GFX_MHz);
 
-		idx = gt0_is_gt ? SAM_ACTMHz : GFX_ACTMHz;
-		if (!access("/sys/class/drm/card0/device/tile0/gt1/freq0/act_freq", R_OK))
-			gfx_info[idx].path = "/sys/class/drm/card0/device/tile0/gt1/freq0/act_freq";
+		set_graphics_fp("/sys/class/drm/card0/device/tile0/gt1/freq0/act_freq", gt0_is_gt ? SAM_ACTMHz : GFX_ACTMHz);
 
 		goto end;
 	}
@@ -6529,52 +6519,44 @@ static void probe_graphics(void)
 next:
 	/* New i915 graphics sysfs knobs */
 	if (!access("/sys/class/drm/card0/gt/gt0/rc6_residency_ms", R_OK)) {
-		gfx_info[GFX_rc6].path = "/sys/class/drm/card0/gt/gt0/rc6_residency_ms";
+		set_graphics_fp("/sys/class/drm/card0/gt/gt0/rc6_residency_ms", GFX_rc6);
 
-		if (!access("/sys/class/drm/card0/gt/gt0/rps_cur_freq_mhz", R_OK))
-			gfx_info[GFX_MHz].path = "/sys/class/drm/card0/gt/gt0/rps_cur_freq_mhz";
+		set_graphics_fp("/sys/class/drm/card0/gt/gt0/rps_cur_freq_mhz", GFX_MHz);
 
-		if (!access("/sys/class/drm/card0/gt/gt0/rps_act_freq_mhz", R_OK))
-			gfx_info[GFX_ACTMHz].path = "/sys/class/drm/card0/gt/gt0/rps_act_freq_mhz";
+		set_graphics_fp("/sys/class/drm/card0/gt/gt0/rps_act_freq_mhz", GFX_ACTMHz);
 
-		if (!access("/sys/class/drm/card0/gt/gt1/rc6_residency_ms", R_OK))
-			gfx_info[SAM_mc6].path = "/sys/class/drm/card0/gt/gt1/rc6_residency_ms";
+		set_graphics_fp("/sys/class/drm/card0/gt/gt1/rc6_residency_ms", SAM_mc6);
 
-		if (!access("/sys/class/drm/card0/gt/gt1/rps_cur_freq_mhz", R_OK))
-			gfx_info[SAM_MHz].path = "/sys/class/drm/card0/gt/gt1/rps_cur_freq_mhz";
+		set_graphics_fp("/sys/class/drm/card0/gt/gt1/rps_cur_freq_mhz", SAM_MHz);
 
-		if (!access("/sys/class/drm/card0/gt/gt1/rps_act_freq_mhz", R_OK))
-			gfx_info[SAM_ACTMHz].path = "/sys/class/drm/card0/gt/gt1/rps_act_freq_mhz";
+		set_graphics_fp("/sys/class/drm/card0/gt/gt1/rps_act_freq_mhz", SAM_ACTMHz);
 
 		goto end;
 	}
 
 	/* Fall back to traditional i915 graphics sysfs knobs */
-	if (!access("/sys/class/drm/card0/power/rc6_residency_ms", R_OK))
-		gfx_info[GFX_rc6].path = "/sys/class/drm/card0/power/rc6_residency_ms";
+	set_graphics_fp("/sys/class/drm/card0/power/rc6_residency_ms", GFX_rc6);
 
-	if (!access("/sys/class/drm/card0/gt_cur_freq_mhz", R_OK))
-		gfx_info[GFX_MHz].path = "/sys/class/drm/card0/gt_cur_freq_mhz";
-	else if (!access("/sys/class/graphics/fb0/device/drm/card0/gt_cur_freq_mhz", R_OK))
-		gfx_info[GFX_MHz].path = "/sys/class/graphics/fb0/device/drm/card0/gt_cur_freq_mhz";
+	set_graphics_fp("/sys/class/drm/card0/gt_cur_freq_mhz", GFX_MHz);
+	if (!gfx_info[GFX_MHz].fp)
+		set_graphics_fp("/sys/class/graphics/fb0/device/drm/card0/gt_cur_freq_mhz", GFX_MHz);
 
-	if (!access("/sys/class/drm/card0/gt_act_freq_mhz", R_OK))
-		gfx_info[GFX_ACTMHz].path = "/sys/class/drm/card0/gt_act_freq_mhz";
-	else if (!access("/sys/class/graphics/fb0/device/drm/card0/gt_act_freq_mhz", R_OK))
-		gfx_info[GFX_ACTMHz].path = "/sys/class/graphics/fb0/device/drm/card0/gt_act_freq_mhz";
+	set_graphics_fp("/sys/class/drm/card0/gt_act_freq_mhz", GFX_ACTMHz);
+	if (!gfx_info[GFX_ACTMHz].fp)
+		set_graphics_fp("/sys/class/graphics/fb0/device/drm/card0/gt_act_freq_mhz", GFX_ACTMHz);
 
 end:
-	if (gfx_info[GFX_rc6].path)
+	if (gfx_info[GFX_rc6].fp)
 		BIC_PRESENT(BIC_GFX_rc6);
-	if (gfx_info[GFX_MHz].path)
+	if (gfx_info[GFX_MHz].fp)
 		BIC_PRESENT(BIC_GFXMHz);
-	if (gfx_info[GFX_ACTMHz].path)
+	if (gfx_info[GFX_ACTMHz].fp)
 		BIC_PRESENT(BIC_GFXACTMHz);
-	if (gfx_info[SAM_mc6].path)
+	if (gfx_info[SAM_mc6].fp)
 		BIC_PRESENT(BIC_SAM_mc6);
-	if (gfx_info[SAM_MHz].path)
+	if (gfx_info[SAM_MHz].fp)
 		BIC_PRESENT(BIC_SAMMHz);
-	if (gfx_info[SAM_ACTMHz].path)
+	if (gfx_info[SAM_ACTMHz].fp)
 		BIC_PRESENT(BIC_SAMACTMHz);
 }